(Gouach co-founder here) We're happy to be on the front-page, here to reply to any of your (many) questions!
We've been testing our batteries for 3+ years on an existing free-floating mobility fleet with our friends from Pony in France, they've been sustaining heat, cold, rain, snow, shocks, people throwing them in rivers, etc, and we've been able to improve them incrementally!
Today we're very proud of our product: it matches the performances of the best brands, it offers connectivity, and we plan to open-source the protocol and make it hackable, so you anyone can use it on any bike!
For now we've reverse-engineered and reimplemented major protocols (Bosch, Bafang, Brose, etc)
(BTW: we've been trying to reach out to Louis Rossman to talk about what we do on his Right to Repair podcast, but couldn't reach him, perhaps he's here, or someone could ping him to know if he'd be interested? we love what he does and he was a source of inspiration for us!)
Oh: and of course, since this is HN, I have to mention that we coded our firmware in Rust!
It should be fairly easy to integrate them into Apple's and Google's FindMy networks, as they are BLE-enabled. Maybe that's your plan? This is the kind of improvement an open source firmware would enable (though if you document the internals well enough, we could also bring our own microcontrollers or custom firmware).
Anyway, I am itching to buy one, but I do not own an e-bike yet (just a few old "La Poste" batteries I would like to salvage the cells of). I will be in the market of an e-bike next year, and would love it if your battery was an option offered by bike shops with new bike purchases.
Have you considered expanding this idea to more than just ebikes?
For example at least here in the US lithium ion tool batteries come with lots of different connector shapes just to lock users into a brand and are not repairable. Manufacturers charge a lot for the batteries, often more than the tools, and if (when) they go bad they just have to be thrown out. Manufacturers even occasionally "upgrade" their battery designs so that they're not backwards compatible to force purchase of new batteries for newer tools. A universal repairable tool battery would likely be a big hit!
Another use case might be USB power packs. These are all sealed and not repairable. They go bad after awhile and the whole thing is waste when it's most likely just a single cell failing.
'Oulipo' nice username, you have a background in litterature?
alex vallette here (cofounder and ceo): shipping in the usa will resume in september. we had to suspend because of tarifs but now we have a warehouse on the east coast so things should be much more optimized as the tariffs will apply only on cost of goods ans not on the consumer price. subscribe to the newsletter to stay tune (we only send one mail every two weeks)
Hi!
Thanks for coming here.
I have a question - how does the device aid in identifying in which cells have gone bad, and then do the necessary rebalancing to match the load level of the cells in the string?
Also, cell replacement is a concern in EVs that placing in a cell of different make and age to the existing ones will mean that cell will have a different charge curve to the others, making very easy for the pack to go 'out of sync' again. How do you address this issue?
You also mentioned that you spent a huge amount of time on making sure the contacts stay in place during the shaking that comes with riding a bike - which is super important as jumpy contacts could cause DC arcing which is a fire hazard.
How would you ease the concern that such a thing absolutely cannot happen?
(Gouach cofounder) There's an app which shows you the voltage level of each cell, and the battery will auto-rebalance them!
For second-life cells, you indeed have to match the cells, we don't necessarily expect people to do that themselves, but we will partner with battery recyclers to get second-life cells, test and match them, and sell back those packs at a lower price as an additional revenue stream for the recycling industry!
Our battery would be perfect for this kind of use-case
For the shaking of contacts, rest assured that: our batteries get tested by third-party authorities like any other batteries, and go through intense stress-test (check https://www.instagram.com/p/C-c_NEbtE4N/ for an example)
And as a second proof, our batteries have been in use in a free-floating mobility startup, Pony, for around 3+ years, they have been subjected to all kind of heat, cold, rain, snow, people kicking bikes, people throwing bikes in the river, etc, and they are working great!
A cryptography angle in the article. Would this be illegal in the US under DMCA?
One of the biggest compatibility challenges, Vallette said, was finding a way to work with Bosch's mid-drive motors. The communications between a Bosch motor and battery are encrypted; after "a serious effort," Gouach's app and battery should work with them, Vallette said.
It really depends. The DMCA does have limited exemptions for reverse engineering for interoperability. The EFF has a good overview: https://www.eff.org/issues/coders/reverse-engineering-faq (search for DMCA). My personal takeaway is that this question cannot be definitely answered outside of court.
And it should soon be illegal under EU right to repair law as well.
France has some reverse engineering exemptions, and I believe compatibility is one of them.
...uhh, yeah, certainly seems like a buried lede. What precisely can I do with Gouach's app and a Bosch mid-drive?
We managed to reverse-engineer the protocol and to make our battery communicate with the Bosch controllers!
What happens when Bosch changes the protocol / encryption just for the heck of it, are you guys back to square one?
> What happens when Bosch changes the protocol / encryption just for the heck of it
Bosch old batteries don’t work with their own new controller anymore. Not saying it will never happen but Bosch can’t do that every week either.
And there'd still be all the already sold controllers, including brand new bikes at retailers. These things don't exactly have over-the-air updates, they are designed to just work forever with the firmware they ship with
There are stick vacuum cleaners with wifi connectivity.
Yes, but that's not the way Bosch builds their stuff
Are you sure? My Bosch dishwasher has wifi connectivity and a companion app.
BSH Group which builds household appliances for Bosch Home is not related to Bosch eBike Systems in any way.
They're geographically and organisation-wise so far from each other, they're basically two different companies.
If I was an asshole designing such a protocol, I would design two or three protocols, specifically so I could disable one via an OTA when somebody reverse engineers it. My real batteries would note the authentication failure, and try protocol number two, their firmware aware of the design from the very start. The people who reverse engineered protocol number one would be hosed until they can reverse engineer the second one, because this would be the first time they even see the second protocol. Do this enough times, and the third parties doing reverse engineering run out of customers willing to wait for them to fix it every time. Hell, you can also just make the BMSs support OTAs. OTA a new firmware with new encryption, force REs to re-solve the problem, since of course the OTA for the stock BMS's stm32f104 will not apply to their board's CH23FVQTZM123123.
There are in fact, a few devices out there that did precisely this and successfully hosed reverse engineers (ask me how i know).
Don’t ever depend on reverse engineered protocols for anything you care about. This game of cat and mouse only has one end -- the manufacturer is at a significant advantage.
I tip my hat to this team for successfully reverse engineering, a encrypted protocol. But if they really think they can sell something based on that, I rescind that hat tip because that is fucking insane. There are just so many ways that the manufacturer could fuck with them. And the reverse logistics of shipping back a large battery for all those pissed-off customers who just want a refund are going to cost a lot of dollars.
I personally would not put a cent into this company unless they agreed to only ship products for devices that already support completely normal interoperability. This business of reverse engineering and attempting to sell based on that is going to be a money drain that kills them (thus ending all customer support). I am willing to bet that they have not even priced out ($$$) the cost of a return to them, nor estimated what percent of customers will need it when the encryption changes or something else doesn’t work.
Is this a problem due to bad cell quality control? Car-sized lithium batteries are lasting 200,000+ miles. Why aren't e-bike batteries?
In my experience, virtually everything is less reliable on a conventional bike, than on a car. Many of the consumable parts last a couple thousand miles at most. This may be due to differing user expectations, or the fact that a bike is more sensitive to added weight. As a rider, it's not objectionable because everything is also more maintainable by a reasonably handy person. I'd rather fix the bike once in a while than ride a permanently heavy bike.
What I can't guess is how this translates into expectations for the components of an e-bike. There must still be a limit to how much size and weight a rider is willing to tolerate.
On the other hand, maybe a high quality battery would last a long time and not need service, but the market isn't ready to believe it.
Yes, it's about weight.
Basically as long as it pass safety regulations, manufacturers will aim to make the lightest (and cheapest) parts.
That's why they use plastic in low-end bikes and carbon/titanium in high-end ones.
You could put motorbike brakes on a bike, and a set of pads would last you a lifetime.
But with so much weight there, the bike would feel unbalanced and hard to handle.
So you'll need to put weight elsewhere to find balance.
And soon enough, you'll have a bike weighting 50kg.
Nobody would want to come near this monstrosity.
People legitimately want a bike that they can power with their legs and handle easily when they are not riding.
Keep in mind that a single car tire is heavier than a whole road bike.
It necessarily results in less atoms, and faster wearing.
First, plastic frames are almost unheard of. There's been a few models here and there, but it's so brittle and it needs so much overdesign to compensate that it doesn't make sense over simple steel. Second, you have it entirely backwards. The lighter materials cost more, not less, because they're more difficult to work with and it's more difficult to get the same strength out of the frame while using less material. As you correctly point out, fewer atoms -> weaker structure. So designers how to work out the geometry to counteract that effect.
> First, plastic frames are almost unheard of.
That's why I talked about "parts", not "frames".
Cheap pedals and cheap brake levers? Plastic.
> The lighter materials cost more, not less
Plastic is lighter and cheaper than steel and aluminium.
Carbon is lighter than steel and aluminium but much more expensive.
I assumed you were talking about the frame, since you mentioned titanium and carbon fiber. Pedals out of those exist, but they're not exactly your run-of-the-mill materials, even on higher-end bikes. Honestly, carbon pedals sounds like a shitty idea. Controls pretty much stop at aluminum or even plastic in the case of shifters, since they don't take very big forces.
Basically all high-end pedals include some kind of titanium or carbon
Totally agree with this. eBikes are already too heavy for my tastes.
Having the motor means people don't care about things like slow rolling tyres, heavy finishing kit or the weight of the transmission to handle the extra torque.
That in turn means you need heavier brakes to stop.
Luckily not every bike has to be the same and we can pick and choose as needed. I'd rather have a lighter bike and have to service it once a year (if that) but that's just me.
Now that the edit window has passed, I realize that I have to add a correction or a caveat. I realized this when I added a drop of oil to my brakes. The car is "unreliable" too, but comes with expectations for periodic maintenance that replaces those parts. All fluids are unreliable. That might even deserve to be a law of engineering.
In fact, when I add up the time and money spent taking care of the periodic maintenance of my car, which involves driving it to the mechanic's, it's way more than what I would consider to be remotely acceptable for maintaining my bike.
I think that you got it right, expectations for cylcing are different. Even avid cyclists could never hit the kilometres travelled by your average car user in a year. Being a lot more expensive as well cars need to last longer for the cost benefit math to make sense. If your car broke every in 10,000kms you'd be livid, out of action constantly. If your bike breaks down, you can probably fix it that afternoon if not on the spot. Worst case you can probably walk it the rest of the trip.
That's where the e-bike is crossing barriers a bit. People will ride them much further, and getting the e-drivetrain repaired can be a real time and money sink. So you want it to be reliable, more reliable than the rest of your bike even.
> Even avid cyclists could never hit the kilometres travelled by your average car user in a year.
According to different sources, the average kilometers travelled by motorists are under 25k km/year (including Europe & US).
You'd be surprised by how many amateur cyclists ride more than that each year.
25000km is 250 100km days per year. That's a lot.
In France for example the average yearly distance travelled by car is closer to 12000km not 25000. More achievable but still a lot.
What a strange way of counting 25 k km ;) shouldn't you say 25000km or 24Mm?
25000km/year is ultracycling territory for amateur cyclist. Yes some people do it, a lot definitely not and I don't think many of them have a full time job.
I wrote first "25k" because that's how I usually write on other platforms, and then I remembered that I'm on a US website, so I felt the need to add a unit.
Sorry!
And if I had written 25000, I would have been afraid of people telling me that it should be 25,000 or 25 000
Thousand is frequently written as k or K, at least in polite society (metric).
you never say kk for one million though. k in km stands for 1000meters already.
Smoots
> You'd be surprised by how many amateur cyclists ride more than that each year.
You wouldn't.
As an 8k km/yr cyclist with a lot of cycling friends, I can tell you that 12.5k/yr is extremely high for an amateur. Sure, there are some, but a truly tiny proportion.
8k/year eats bikes, BTW. I used to wear out rims regularly before I switched to disks and chains/sprockets didn't even last a year (on a fixed gear bike).
First, this is what OP said:
> Even avid cyclists could never hit the kilometres travelled by your average car user in a year.
And you tell it yourself:
> Sure, there are some
So, if OP really thinks that no cyclist can ride more than what an average motorists drive a year, then even "but a truly tiny proportion" would appear as a surprise to them.
Also, just looking at my Strava right now, amongst the 30 friends that I follow (I'm picky on my follows), more than a third are on their way to ride more than 25k this year.
The most advanced is going to reach 23k by the end of the day based on his current numbers and habbits.
How, where and when you ride your bike will be a huge factor in how much wear it gets.
For instance, my commuter' chain usually get less than half the mileage that my road bike' chain get because city is dirty, I ride no matter the weather, don't clean the chain after each ride and keep putting strong torque since I constantly have to stop and start.
Same goes for brake pads: when I commute I hardly do 200m without having to brake, whereas I can go for 20km without having to touch my brakes on my road bike.
> So, if OP really thinks that no cyclist can ride more than what an average motorists drive a year, then even "but a truly tiny proportion" would appear as a surprise to them.
I said an avid cyclist, which is quite undefined so fair enough. What I meant was an enthusiast still, not a sport rider or someone you could consider an amateur athlete (many road riders).
Road riding gets you a lot of KMs and hours in the saddle too, like you said in quite a specific wear pattern. I ride for hours on my MTB and my commuter but would never come close to the hours and KMs of road riding, and I will be replacing my MTB sprocket and brake pads much sooner than my commuter.
I think we're more or less on the same page though, and since all cities and cultures are a bit different we could be talking past eachother without specifics at which point my general comments go out the window anyway.
Yeah if you do mainly MTB, I can definitely see why we had a hard time understanding each other!
That's partly why when people talk to me about "how many km do you ride each year?" I respond in hours on the saddle.
Just for the sake of disclosure, and to provide one data point, I ride 8 miles per day, 5 days a week, year-round, on two bikes (summer and winter). That's about 2600 km/y. Maybe add a few hundred km for occasional weekend recreational rides, and getting around town.
People are quite careful with their cars. People are really not careful with bikes, including e-bikes.
I think that's a generalisation too far. :P
I don't care a hoot about my car, I wash it once a year whether it needs it or not.
It's the same for a commuting bike. My road bike on the other hand gets washed, tyres pumped, transmission cleaned and lubricated on every ride.
I think most club riders would be just the same.
It's not just vanity, dirty transmission is more tiring to pedal when you're trying to keep up with a group and when you're coming down hill at 50mph you want to know your brakes will work.
Tell my teenagers ;)
And look at the average railway station bike parking.
Bikes have it rough. They have crappy suspension, usually are used on roadways that are much worse than the ones that cars ride on, they have to regularly deal with impact and g-forces that you rarely see in cars outside of actual accidents and people drop them all the time. I've been working on bikes all my life and if there is a form of bike damage that I have not seen yet it would amaze me.
> And look at the average railway station bike parking.
Yeah there definitely seems to be a polarised dichotomy here.
Bikes are either very pampered or have a squeaky chain and gears that don't index properly with nothing in between!
>I wash it once a year whether it needs it or not.
I admire that, I used to wash my truck once a year too, until I ran out of time.
> There must still be a limit to how much size and weight a rider is willing to tolerate.
This is true for bikes, and after decades of marketing and fearmongering, basically the inverse is true for cars.
I'm saying this as a european non car-owner who's never been to the US, but my impression of car brain from over here is that anything that approaches light-weight is seen as a "death trap" by a majority of US drivers, especially because the rest of car users drive cars that literally have the size of WWI tanks.
My favourite are utes (Australia) / trucks (US) with a hard cover over the tray are.
Glorified shopping cart.
Might as well buy a hatchback.
Battery cells are generally binned like many ICs and the best cells go to cars and other high margin, high performance, or safety critical goods. The lower quality ones go to more cost conscious markets like the ebikes, where problems in quality control can definitely show up, especially if the OEM isn’t careful in how they spec the deliverables QA on the battery manufacturer’s side.
How are ebikes not in the high margin category? The Bosch batteries sell for €1000/kWh at the pack level.
I think it's the BMS, Batteries in cars usually get used between 20/80% and have active cooling and heating while ebikes don't.
High margin means stuff like aerospace, defense, and biotech - although a more accurate phrasing might have been “high value add”
How many cycles does the ebike battery go through in 200k+ miles? An EV car does ~300 miles/cycle. So 200k miles = 667 cycles.
Cycles is not the only variable in play here:
- Depth of Discharge - how often you go from full to low battery? Going twice from 80->30 (which accounts to a single cycle) is much better than single 100->0 cycle
- Thermal management - what are cell temperatures when battery is being charged? Maybe it is charged in direct sunlight? This will kill battery pretty fast. At what temperatures are the cells when driving the ebike?
- Ebike/scooter probably being charged to 100% more often than necessary.
- Did you leave your battery at winter completely discharged or fully charged in your garage? Bad.
TLDR: Info I gathered about reading how to take care of Lithium NMC batteries which are so widespread.
i get about 90km of range from a 500Wt Bosch battery. Thats running at full power the whole time.
With 600Wh battery and Shimano Steps E5000 in lowest support level I can easily ride 250km/charge
That is amazing performance. I usually get about half that.
I usually ride faster than the motors limit, so it's really just acting like a push, and most of the battery is spent dragging me up a really big hill i live on. Everywhere I ride down in town is pretty much flat.
Battery service life depends on many other factors besides just manufacturing quality: time, operating temperature, number of charge cycles, charging parameters, etc. On top of that, each cell design is optimized for some set of operating parameters: load, energy density, specific energy, price. It's all variables, so you'd have to narrow that question down quite a bit to even hope to have a reasonable answer.
They last about the same number of cycles, but a cycle on a car is 250-350 miles, a cycle on a typical ebike is 20-40 miles.
Ebike BMS will also drive the batteries harder (allowing to reach deeper empty/full states) since their design lifetimes are shorter than cars.
(Gouach co-founder here) Car-sized batteries last long because they have so much redundancy, that even when multiple cell fails, you barely notice it. It's very different in a smaller e-bike battery packing 40 or 80 cells.
Cells aside, cars have very good suspensions, and their batteries have been designed with very pricey component to eliminate shocks and vibrations.
On e-bikes, most batteries will have to sustain those, and we've seen a LOT of commercial batteries who were out of order for a simple $5 electronics component which was broken, and which couldn't be replaced because the battery was not made to be repaired (soldiering, glue, etc)
discharge rates
I imagine it’s partly due to bad quality control and engineering. No active cooling, probably a not well optimized battery management system. The batteries probably have more shock from lack of suspension.
On the user side folks may not be keeping them optimally charged.
There's a lot of noise around EVs between range anxiety, recycling, catching fire etc. Is this riding on non-existent problems or is it solving an actual real problem which I've been lucky to avoid so far?
I don't do e-bikes but I've had E-vespas and e-scooters and replacing a cell isn't really something I've had in mind. I've had lots of failures, none of them were from the battery. They all died too, before the battery.
The next step of the lifecycle is recycling, and that's done by professionals who do have arc welders, so they don't require such convenience
We're going to produce larger batteries for vespas, golf carts and scooters too!
Our repairable battery is actually quite convenient even for recyclers: many studies have shown that if you can get pristine cells, without all the casing / electronics / plastic parts as you're recycling the cells, you get back a much more pure recycled lithium at the end of the process!
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>> It keeps you updated on the status of cell performance and heat through a Bluetooth-connected app
why an app? Why not a simple light or error code on device?
There is both! But the app obviously has a few advantages in our setup:
- it gives much more detailed and fine-grained informations
- it allows user (optionally) to register for automated safety alerts
- but more importantly, it allows users to override themselves the communication protocol of the battery, to adapt it to any bike
For now we've hardcoded Bosch, Bafang, Brose and a few others (more coming), and we plan to open-source the communication protocol soon so that anyone can upload their own WASM code on the battery to talk to any controller!
1- might make the (waterproof) case harder to build
2- finding the right dead battery among 18650 batteries is requiring more hints than just "something is wrong"
3- marketing / convenience and probably you can order your dead battery straight from the app
4- monitoring battery charge, battery life / cycles / etc.
5- no idea :-)
Just speculating, but I guess there are a lot of reasons why a bluetooth app makes sense
I think the idea might be that you don't need to check the battery health yourself but instead you get pinged when a cell's getting close to dead
Your second point made me chuckle ;)
Why not both? I'd love an error LED to tell me something's wrong, maybe (maybe) with complicated blink codes that I can count and recount to determine which cell is bad or what action to take, but I also want a Bluetooth app to access the actual data: live cell voltages, currents and temperatures, estimated storage capacity and cell health, lifetime charge cycles and total power delivery... Give me all the data!
I don't want to increase the cost and complexity, and reduce the runtime of the thing with an onboard tiny LCD and an array of buttons to navigate menus. The interface could be available over a Bluetooth app, or or a self-hosted webpage, or make it show up as USB mass storage or a USB virtual serial port, or an actual RS232 or RS485 or TTL serial port, or I can grab it off a storage device with an EEPROM clip, or hook up my Tag-connect cable and a bus pirate and get I2C or SPI or whatever unnecessarily custom UART protocol you want to invent, or I can buy your dedicated HMI device with the LCD and buttons connected by a custom cable (don't want to buy yet another, I already have too many kicking around from decades of work with random industrial VFDs and PLCs and stuff), or I can hook up my MSO to some test pads and read the signals directly... But not everyone has all those tools and cables.
Like it or not, the standard has become a Bluetooth app. I wish the standard was a self-hosted webpage, so I could connect my laptop to a buried RJ45 connector, set a static IP to point my NIC at the right subnet (or the device could embed a router to assign my laptop a compatible IP over DHCP, but most don't), or I could turn on an integrated wifi adapter in the device, ignore and revert the protestations of my device and OS that the connection was unsuccessful because it can't ping connectivitycheck.android.com or captive.apple.com or msftconnecttest.com or whatever through the battery pack SSID. But by the time your user manual tells the user to go to their network adapter properties and set their IP address to 10.10.0.2 (on their iPad, LOL) you've lost most people long ago.
Like it or not, the standard has become Bluetooth and an app, and not without compelling if frustrating reasons.
You can't see what cells are low or have high IR with just a light on the device easily.
Maybe a small screen on the device would work, since it has replaceable cells you do need to know more details about which cells are weak.
Bluetooth connect apps are pretty much commodified at this point.
If one product has an app, and the next one doesn’t, people will choose the one that does.
so long as the protocol is simple enough to be recreated in nRF Connect, Bluetooth is fine. A proprietary bluetooth connection would be gross, though.
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It would be cool to see a fully open source ebike. Sort of like a framework (the hardware company) of ebikes.
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We're only working on the battery, but we plan to open-source at least the app and make the communication protocol extensible with "plugins", in order to let users configure their batteries for any controller protocol!
What would you like to see beyond what you can already do, i.e. buy a bike (or frameset, wheelset, groupset) and conversion kit?
I think the proposition is an open-source "conversion kit". Battery, charge controller, motor controller, sensors, display, source-code, specifications, etc. Built with some sort of standard so parts are easy to swap/extend. I like the idea
Like it's mentioned in the article the motor controllers themselves are closed source so they have to hack the protocol in order to plug the battery into it.
What if all the software and hardware systems of the bike were open source, not just the battery.
Great idea! I try to buy devices based on 18650. It should be the new AA standard, right?
But the so called 'USB' 18650 torch I got has a custom magnetic charger, yuk!
The last 3 hand-held vacuum cleaners are 4x18650, but have all been welded, and non replaceable.
Bike battery is already flagging, but newer replacement design has different connector.
Having a universal bike battery like this sounds perfect!
Even better if they make it into a generic power bank design; 48V would be perfect for connecting to solar panel for charge, then use it on the bike, lawnmower, laptop, maybe a small 230V inverter add-on.
Or a smaller 8/12 bank for pushing back against power tool company 'lets change the battery standard' every 2 years so that we can sell the same tools again.
Nice to see some attempt to fight this locked-down throw-away manufacturing obsession. Well done!
(Gouach co-founder) Thanks for your comment! That's exactly what we're trying to do, giving back power to people by providing them stuff that they truly own, they know how it works, they can assemble and repair them (or ask their local bike-shop to do it) without any vendor lock-in!
> Even better if they make it into a generic power bank design; 48V would be perfect for connecting to solar panel for charge, then use it on the bike, lawnmower, laptop, maybe a small 230V inverter add-on.
Great idea, I would love to see them offer solar chargers as well.
I was thinking of designing an open source UPS at some point, I guess I could architect it around this battery (though LiFePo would make more sense). I will have a look at the docs when they are out, I hope there's a communication/diagnosis bus, though Bluetooth would work as well.
Nice. I think I saw mention of support for custom WASM plugins somewhere.
From a device manufacturer's perspective, it is mainly a safety and reliability issue.
The form factor might be (mostly) standardized, but the cells themselves are not. There's a huge amount of variation between them, and using a cell improperly can quickly lead to some very nasty fires.
This means user-replaceable bare cells go right out the window, and you're left having to build a custom protection circuit for the cells you want to use - which means you essentially end up with custom batteries.
The solution might be a standardized way for the cell to communicate its health and capabilities to the device using it - but good luck getting the industry to adopt it. It provides no immediate benefit to the consumer while making the product more expensive, so they'll only do that when the government forces them to.
I like the idea of Batteries as a Service, and I could see it working in some US cities for scooters.
Many consumers just don't want to worry about battery health. Reportedly, battery degradation anxiety is driving down used EV prices in the US.
(Gouach co-founder here) A lot of people would prefer to not have to care, but many of them do care because they know it's the major "consumable" part of their $3000+ e-bike investment, and they want to know if it will last long, if it's robust, and if it can be repaired in case it's needed
Additionally, we've seen more and more customers wary of the environmental and social cost (children mines, etc) linked to lithium batteries, and who are looking for more durable solutions
In China they have car battery swap stations. For such batteries, owenership does not make much sense, so a subscription model indeed seems logical. The monthly fee covers the cost it takes for the company to replace worn cells; electricity could be charged separately for cars. For scooters, since the batteries are easy to swap yourself, buying and swapping a new battery is not that big of a deal, so I don't see subscriptions working as well there as for cars.
(Gouach co-founder) Yes! Our battery would be perfect for a swap business, they could easily fix damaged batteries, repair cells (only $50, instead of buying a new battery at $300 retailer price), and at the end, they could even retrieve used cells to sell them back for energy storage applications!
Gogoro is a borderline scam.
There are not multiple battery providers. You can only get batteries through gogoro and they dictate the price (it govt fixed for X amount of year and then who knows what happensl. Till recently you couldn't charge the scooter/batteries at home (even now it's made impractical)
You in effect are renting your vehicle
It's only successful in Taiwan due to slick marketing and intense nationalism
I think it is a pretty god idea. It may remove quite a bit of battery waste.
it's a cool idea for small setups, but very expensive per kwh.
if you want the same kind of style diy-er box-for-batteries I suggest the Trampa offerings. Similar focus on safety and novice level DIYer capability but much larger capacities and arrangements.
Very nice battery boxes! Our product is expected to go down in price as we increase the production.
Our product also comes with a high-end connected Battery Management System (the "brain" of the battery), and with a sturdy and fire-resistant aluminum casing!
I wonder if this will allow flying with an ebike battery in disassembled form. The regulations allow up to 100Wh per battery, and an unlimited number of batteries, so transporting the individual cells should be okay, at least in theory.
Lugging an entire suitcase full of 1 kWh worth of batteries might not technically be against regulations, but I imagine you'd be signing yourself up for a long series of headaches at the security checkpoint anyway. To be honest, if I knew that security wouldn't stop me because "it's not technically against regulations", that's exactly what I would do if I wanted to bring down a plane.
Right, that's basically the problem, if one wants to travel by air with an ebike without hassle, there's no real option to do so.
There really needs to be standardization of battery packs for ebikes instead of proprietary ones, so that one could rent a battery at their destination.
At that point why not just rent the whole bike and not need to bring the large object onto the plane?
Because ones bike is a carefully selected item perfectly fitted to ones body shape and preferences, whereas the battery is simply a line replaceable unit.
That's such an edge case though.... what about my fine tuned piano? Or my aquarium? At some point personal luxuries don't have to be accommodated for
Even as an avid cyclist who fully understands geometry and the personal connection one may have to one's bike, I agree with you.
Privileged enough to fly somewhere specifically to ride bicycles? C'mon, I think you can find a good enough bike to rent when you get there.
Absolutely you can. The places in France and Spain I've flown to just suggest you bring your own pedals, so they match your shoe cleats; they'll fit them before your hire. You can usually bring your own saddle too. It's far more convenient than bringing the bike.
I've also done it the other way, my main bike has S&S coupling so I could bring it aboard the Eurostar. For touring I prefer my own bike, because I have the racks set up for my panniers, but when I do that, I prefer travelling by ferry/train.
I love it! Even for the lift/shuttling-bike-park crowd, I bet many places would happily install cleat-matching pedals (or your own), your saddle... maybe your grips if you are picky?
I think the intersection between people who ride e-bikes and cyclists who obsess about bike fit is fairly small.
You totally have the option to fly with a regular muscular powered bike.
(Gouach co-founder here) Yes! that's a possibility in theory. You can just remove all the cells, which then become "inert", and the pack set aside. It then only takes 5 min to reassemble them at your arrival.
I would honestly not want to fly on a plane with this or anyone else's ebike batteries. To dangerous.
You don't even want to be in an elevator with them. There are some absolutely horrific videos of how quickly this can get out of hand.
An even bigger model for vans (to get 2 kWh) would be great. But electronics for 48V is still rare and expensive.
Would this be possible in 12V ?
Can we also put LiFePO4 instead of Li-ion ?
We are working on larger models already, and we plan on models for LiFePO indeed!
Subscribe to our newsletter if you want to be informed :)
https://gouach.com
Merci !
An ebike is very weight sensitive. How much extra weight does this innovation lead to?
I would rather have the whole battery be replacable. And when you want to replace, you trade-in your old one for a discount on the new one.
> An ebike is very weight sensitive.
E-bikes tend to be quite heavy, and many of them have designs that are very much not optimized for weight.
> I would rather have the whole battery be replacable.
They are. And the replacements are single-source and are very expensive.
To a degree yes, however I have an ebike and the bosch battery with a it has a 500W battery which is about equiv (if my math is right) to a 28 Ah ryobi drill battery. Those don't exist btw, but if i wanted one and bought 7 4Ah batteries to get the same effect they would cost more than the single ebike battery.
As a single item they are pretty well priced for the power they offer.
I think those batteries have their own BMSs, plus casing etc, that adds to the cost. The story as I can understand it is about being able to swap out individual cells which won't have those overheads.
The battery itself is 3.3kg, so quite comparable to other models, keep in mind it comes with a sturdy aluminum casing.
What we mean by "replacing" is that you can change the cells of the battery yourself (or by asking at your local bike shop), so you don't need to trade-in the whole battery! This makes you gain time and a lot of money!
Thanks for the answer. 3.3kg is quite light.
Pedal powered bikes are very weight sensitive. The average e-bike (at least one that would use a fat battery pack like the on pictured in the article), are less weight sensitive.
The RadKick 7 (which RadPower calls a "lightweight bike" weighs 55 lbs.
Racing bikes like the $10K Trek Domaine Carbon weighs less than 30 lbs, but has a much slimmer (and lower capacity) battery pack than what Gouach seems to be targeting.
Very little I'd bet and location of the weight is far more critical to overall utility. Hopefully this is well thought out.
This is a great idea. Would be wild if they could support switching on the fly between 32 and 48v for a range/speed option. That gets complicated though.
Most e-bike providers will buy their switching logic based on the voltage in use, a driver for 48V would be substantially more expensive than one for 32V. There is also the whole charger setup to consider so yes, that gets complicated.
Doesn't need to. Power is power.
This guy is right, the premise of switching doesn’t make sense, power is power.
I only remember when I built my own batteries, I would get more range at lower volts because at about 40+km/hr you end up pushing wind and range goes way down. So yeah, technically power is power, but it's fun to go 50km/hr if you don't have far to go.
There probably aren't many EVs that can't regulate voltage across motor poles between 0 to +battery pack(or -1/2 to +1/2 pack) voltage...
Did your controller only have one power setting?
Yeah it did. It was fairly burly to begin with and I modified it with a stronger mossfett. This was back in 2007 when ebikes were very fringe. I would get packs of defective DeWalt drill batteries on eBay to harvest the good cells and build my own packs. I spent almost as much time building the bike as I did riding it. Ebikes.ca and endless sphere forums were full of help.
Cue Bob Parr meme...
Changing the voltage doesn’t change the amount of power being used, the only thing that would change is the ampacity (which only impacts conductor size, in this case).
480 watts == 10 amps @ 48V == 15 amps @ 32V
An electrically commutated motor (brushless DC) in an e-bike will almost certainly have a speed controllee, if you want more range you simply have to go slower ;)
Reconfiguring a battery pack with the same number of cells doesn't change the power contained in the pack. However lowering the voltage will lower your top speed (if not already artificially limited by the controller) and raising the ampacity of the pack may allow you to get more torque from the motor if you haven't saturated the motor and you change the controller settings to pull more amps from the battery.
Ah yes, DC motor speed is controlled by voltage. Glad to see Cunningham’s Law still holds true, thanks :)
I’m much more familiar with three-phase AC induction motors from my day job and the speed on those are (most commonly) controlled by adjusting the frequency with a variable frequency drive while maintaining the same voltage instead of directly controlling the voltage like on a DC motor.
Yeah but the wind kills range much more so at the higher speed 48v gives you and you tend to never run at half throttle.
Balancing will be a nightmare I guess, or just dont do it. Nice idea for the advanced user but I would not let my parents fiddle around with lose 18650 cells for the sake of their house burning down.
I see a niche application but personally hope they get it to market and make it compatible with Shimano. My double sized battery is a frankenbattery: pcb from original with custom printed case fitting onto the original attachment device using the batteries from two original batteries. Measured and balanced of course. Safety is "meh" I guess because DIY. I'd like to replace it with something more properly designed.
I did my masters thesis on how to balance batteries with very little information on each individual battery a-priori! Unfortunately I didn’t get to do experimental stuff because it was the middle of Covid, I only had simulation data. You can do some interesting things, though I wonder how many issues we missed/avoided by working only in simulation.
Edit-edit: wow I got two citations!!! Never thought anyone would read my paper, that’s amazing.
Can I put that into a humanoid
This is such a terrible idea because the packs have to be factory balanced before assembly, and everyday Joe doesn’t have the equipment (or probably the understanding) to do this part properly.
If the packs are not perfectly balanced, the batteries just short into each other and explode, and BMS can’t do anything because there isn’t any per-cell switch (cost).
It’s not just a matter of balancing voltage either, the cell profiles (voltage vs SOC) have to be the same otherwise you end up with 1 cell doing all the work. Simply put, when you mix and match cells of different brands, models, or even ages, they don’t integrate evenly. This results in a few or even just 1 cell doing a majority of the work during both charge and discharge, maybe 10x higher than its safety rating, guaranteed fire…
Also end-user is expected to do the math and input the battery’s total current rating into the motor controller? Yeah, nah, a hundred kids will think it’s cool to set this too high and set themselves and people around them on fire.
The cells which are in parallel will auto-balance when inserted. It's true that putting an empty cell and a full cell in, can indeed lead to a unextinguishble fire due to thermal runaway. But from the factory, cells will be very close already. They will auto balance once inserted (the parallell cells). Every single charger in existence will then balance the series cells actively on every charge cycle. So "terrible idea"? No, but maybe something to leave to the bike shop. Still better than throwing away the pack. And maybe fuses between every cell would help for protection against
(Gouach co-founder here) Exactly! The first kits are DIY for our early adopters, but we are working on an assembly pipeline in France, China and the US for our models in the coming months. Clients (B2C and B2B) will receive pre-assembled batteries
We are also looking for bike-shop owners who want to train on our batteries (it can be learned in one hour or so) to get a new revenue stream by offering to repair and assemble our batteries!
Seems an overly pessimistic take. TFA specifically mentions per-cell temperature monitoring, and I would assume there is also per-cell voltage monitors.
As long as the controller is made sufficiently conservative, there is no fundamental problem: you limit the current according to the cell that heats the fastest and shut down once one cell is near depletion.
Maybe they have even gone a more aggressive route and build a balancing circuit that can route significant current around a low-capacity cell. Or maybe just charging logic to keep as many cells as possible in the 20-80 regime if they will be limited by low-capacity members anyway. There are so many options here.
The Toyota Prius community already has a better solution for this - You can buy remanufactured batteries, then send your used battery back to get a credit. ChrisFix on YouTube has a swap guide for DIYers - it's mostly taking all the interior panels out of the back of the car.
(Gouach co-founder here) This is nice, but when you have an e-bike with a malfunctioning battery that you use for work everyday, you don't want to have the 2/3 months it generally takes for exchange programs.
Plus, once you sent your battery, they either discard it which is not ideal for the environment, or try to remanufacture it, which is very dangerous when it's done on a battery which wasn't designed for it, like ours
Sounds like a challenge: start monitoring individual temperatures, long term recording of performance down to the cell, recommend a mAh value of cell in a particular location, dynamic ohm chips in series with batteries to control differential discharging.
I am not enough of an expert to know if all this could work, but its got to be better than replacing an entire pack at a time to be worth trying
Cells in parallel will stay balanced and act as one big cell even if they're different capacities although they do need to be the same voltage first, but in series they need to be matched in capacity.
Slight mismatches in capacity can be OK in series too, as long as you have a BMS watching the cell voltages to make sure none get too low when discharging and none get too high when charging. The risk is that the lower capacity cells get too low or too high while the overall pack voltage seems fine, causing dendrites to form inside those cells, leading to a short and a scary fire. It really comes down to how well the BMS is designed / programmed and how much you want to trust it.
Most people aren't aware of how dangerous it is to try to "revive" a cell that got too low so this technology definitely comes with significant risks for user error.
It doesn’t magically morph into one big battery, suppose you have 5 different batteries in parallel, 1 new and 4 used different model, and you discharge this assembly at 50A: a large proportion of the current will flow through the lowest IR cell, say 45A of it. But the problem is that cell is only rated for 10A.
So yes, the net current is supposed to be okay, but it’s not, and rather than responding individually to all the other comments I may as well mention that no amount of temperature monitoring will fix this. Temperature sensors don’t detect internal cell stresses that cause spontaneous failures.
Unless they're wildly different chemistries, they'll have an IR that's inversely proportional to SoC and capacity, so you won't get that situation of 1 cell supplying 90% of the current unless it also has 90% of the capacity of the pack. Any cell that discharges a little more will have its IR increase, reducing its share of the current.
(Gouach co-founder here) Most of our users buy brand new cells, and we are working with partners who do have the equipment to retrieve second-life cells and match them in their factories, before selling them as "matched second-life cells packs" back to users for a huge discount :)
Do you honestly think they haven’t thought of that/tried it out?
[deleted]
Let's hope the inane DMCA laws don't get them for decrypting the Bosch battery-motor communication.
If HN had profile pictures, mine would be a Clippy.
I wonder how much they will have to protect against recklessness of the e-bike owners? For example, against the end user sourcing substandard cells, and combining them in inadvisable ways.
I don't have a good profile of e-bike owner behavior about maintaining their own equipment, but what I can say is fewer than 1/5 of e-bikes will stop on red at a 3-way intersection near me (when cars are stopped in the parallel lane, and pedestrians are crossing).
We also see a lot of riding on sidewalks, at speed, to bypass red lights and traffic on a major street here.
That said, the e-bike riders are often wearing helmets as they plow through pedestrians, so maybe their recklessness only extends to the safety of others, and they'll be conscientious about not lighting a lithium battery fire between their own legs.
(Gouach co-founder here) We're happy to be on the front-page, here to reply to any of your (many) questions!
We've been testing our batteries for 3+ years on an existing free-floating mobility fleet with our friends from Pony in France, they've been sustaining heat, cold, rain, snow, shocks, people throwing them in rivers, etc, and we've been able to improve them incrementally!
Today we're very proud of our product: it matches the performances of the best brands, it offers connectivity, and we plan to open-source the protocol and make it hackable, so you anyone can use it on any bike!
For now we've reverse-engineered and reimplemented major protocols (Bosch, Bafang, Brose, etc)
Happy to take any question you might have, and if you're interested, you can order a battery here :) https://gouach.com/products/infinite-battery-complete-kit?va...
(BTW: we've been trying to reach out to Louis Rossman to talk about what we do on his Right to Repair podcast, but couldn't reach him, perhaps he's here, or someone could ping him to know if he'd be interested? we love what he does and he was a source of inspiration for us!)
Oh: and of course, since this is HN, I have to mention that we coded our firmware in Rust!
Looking at your roadmap (I appreciate the transparency): https://gouach.com/pages/roadmap
> Implementing Geolocalisation [sic] on Batteries
It should be fairly easy to integrate them into Apple's and Google's FindMy networks, as they are BLE-enabled. Maybe that's your plan? This is the kind of improvement an open source firmware would enable (though if you document the internals well enough, we could also bring our own microcontrollers or custom firmware).
Anyway, I am itching to buy one, but I do not own an e-bike yet (just a few old "La Poste" batteries I would like to salvage the cells of). I will be in the market of an e-bike next year, and would love it if your battery was an option offered by bike shops with new bike purchases.
Have you considered expanding this idea to more than just ebikes?
For example at least here in the US lithium ion tool batteries come with lots of different connector shapes just to lock users into a brand and are not repairable. Manufacturers charge a lot for the batteries, often more than the tools, and if (when) they go bad they just have to be thrown out. Manufacturers even occasionally "upgrade" their battery designs so that they're not backwards compatible to force purchase of new batteries for newer tools. A universal repairable tool battery would likely be a big hit!
Another use case might be USB power packs. These are all sealed and not repairable. They go bad after awhile and the whole thing is waste when it's most likely just a single cell failing.
'Oulipo' nice username, you have a background in litterature?
alex vallette here (cofounder and ceo): shipping in the usa will resume in september. we had to suspend because of tarifs but now we have a warehouse on the east coast so things should be much more optimized as the tariffs will apply only on cost of goods ans not on the consumer price. subscribe to the newsletter to stay tune (we only send one mail every two weeks)
Hi!
Thanks for coming here.
I have a question - how does the device aid in identifying in which cells have gone bad, and then do the necessary rebalancing to match the load level of the cells in the string?
Also, cell replacement is a concern in EVs that placing in a cell of different make and age to the existing ones will mean that cell will have a different charge curve to the others, making very easy for the pack to go 'out of sync' again. How do you address this issue?
You also mentioned that you spent a huge amount of time on making sure the contacts stay in place during the shaking that comes with riding a bike - which is super important as jumpy contacts could cause DC arcing which is a fire hazard.
How would you ease the concern that such a thing absolutely cannot happen?
(Gouach cofounder) There's an app which shows you the voltage level of each cell, and the battery will auto-rebalance them!
For second-life cells, you indeed have to match the cells, we don't necessarily expect people to do that themselves, but we will partner with battery recyclers to get second-life cells, test and match them, and sell back those packs at a lower price as an additional revenue stream for the recycling industry!
Our battery would be perfect for this kind of use-case
For the shaking of contacts, rest assured that: our batteries get tested by third-party authorities like any other batteries, and go through intense stress-test (check https://www.instagram.com/p/C-c_NEbtE4N/ for an example)
And as a second proof, our batteries have been in use in a free-floating mobility startup, Pony, for around 3+ years, they have been subjected to all kind of heat, cold, rain, snow, people kicking bikes, people throwing bikes in the river, etc, and they are working great!
A cryptography angle in the article. Would this be illegal in the US under DMCA?
One of the biggest compatibility challenges, Vallette said, was finding a way to work with Bosch's mid-drive motors. The communications between a Bosch motor and battery are encrypted; after "a serious effort," Gouach's app and battery should work with them, Vallette said.
It really depends. The DMCA does have limited exemptions for reverse engineering for interoperability. The EFF has a good overview: https://www.eff.org/issues/coders/reverse-engineering-faq (search for DMCA). My personal takeaway is that this question cannot be definitely answered outside of court.
And it should soon be illegal under EU right to repair law as well.
France has some reverse engineering exemptions, and I believe compatibility is one of them.
...uhh, yeah, certainly seems like a buried lede. What precisely can I do with Gouach's app and a Bosch mid-drive?
We managed to reverse-engineer the protocol and to make our battery communicate with the Bosch controllers!
What happens when Bosch changes the protocol / encryption just for the heck of it, are you guys back to square one?
> What happens when Bosch changes the protocol / encryption just for the heck of it
Bosch old batteries don’t work with their own new controller anymore. Not saying it will never happen but Bosch can’t do that every week either.
And there'd still be all the already sold controllers, including brand new bikes at retailers. These things don't exactly have over-the-air updates, they are designed to just work forever with the firmware they ship with
There are stick vacuum cleaners with wifi connectivity.
Yes, but that's not the way Bosch builds their stuff
Are you sure? My Bosch dishwasher has wifi connectivity and a companion app.
BSH Group which builds household appliances for Bosch Home is not related to Bosch eBike Systems in any way.
They're geographically and organisation-wise so far from each other, they're basically two different companies.
If I was an asshole designing such a protocol, I would design two or three protocols, specifically so I could disable one via an OTA when somebody reverse engineers it. My real batteries would note the authentication failure, and try protocol number two, their firmware aware of the design from the very start. The people who reverse engineered protocol number one would be hosed until they can reverse engineer the second one, because this would be the first time they even see the second protocol. Do this enough times, and the third parties doing reverse engineering run out of customers willing to wait for them to fix it every time. Hell, you can also just make the BMSs support OTAs. OTA a new firmware with new encryption, force REs to re-solve the problem, since of course the OTA for the stock BMS's stm32f104 will not apply to their board's CH23FVQTZM123123.
There are in fact, a few devices out there that did precisely this and successfully hosed reverse engineers (ask me how i know).
Don’t ever depend on reverse engineered protocols for anything you care about. This game of cat and mouse only has one end -- the manufacturer is at a significant advantage.
I tip my hat to this team for successfully reverse engineering, a encrypted protocol. But if they really think they can sell something based on that, I rescind that hat tip because that is fucking insane. There are just so many ways that the manufacturer could fuck with them. And the reverse logistics of shipping back a large battery for all those pissed-off customers who just want a refund are going to cost a lot of dollars.
I personally would not put a cent into this company unless they agreed to only ship products for devices that already support completely normal interoperability. This business of reverse engineering and attempting to sell based on that is going to be a money drain that kills them (thus ending all customer support). I am willing to bet that they have not even priced out ($$$) the cost of a return to them, nor estimated what percent of customers will need it when the encryption changes or something else doesn’t work.
Is this a problem due to bad cell quality control? Car-sized lithium batteries are lasting 200,000+ miles. Why aren't e-bike batteries?
In my experience, virtually everything is less reliable on a conventional bike, than on a car. Many of the consumable parts last a couple thousand miles at most. This may be due to differing user expectations, or the fact that a bike is more sensitive to added weight. As a rider, it's not objectionable because everything is also more maintainable by a reasonably handy person. I'd rather fix the bike once in a while than ride a permanently heavy bike.
What I can't guess is how this translates into expectations for the components of an e-bike. There must still be a limit to how much size and weight a rider is willing to tolerate.
On the other hand, maybe a high quality battery would last a long time and not need service, but the market isn't ready to believe it.
Yes, it's about weight.
Basically as long as it pass safety regulations, manufacturers will aim to make the lightest (and cheapest) parts. That's why they use plastic in low-end bikes and carbon/titanium in high-end ones.
You could put motorbike brakes on a bike, and a set of pads would last you a lifetime. But with so much weight there, the bike would feel unbalanced and hard to handle. So you'll need to put weight elsewhere to find balance. And soon enough, you'll have a bike weighting 50kg. Nobody would want to come near this monstrosity. People legitimately want a bike that they can power with their legs and handle easily when they are not riding.
Keep in mind that a single car tire is heavier than a whole road bike. It necessarily results in less atoms, and faster wearing.
First, plastic frames are almost unheard of. There's been a few models here and there, but it's so brittle and it needs so much overdesign to compensate that it doesn't make sense over simple steel. Second, you have it entirely backwards. The lighter materials cost more, not less, because they're more difficult to work with and it's more difficult to get the same strength out of the frame while using less material. As you correctly point out, fewer atoms -> weaker structure. So designers how to work out the geometry to counteract that effect.
> First, plastic frames are almost unheard of.
That's why I talked about "parts", not "frames".
Cheap pedals and cheap brake levers? Plastic.
> The lighter materials cost more, not less
Plastic is lighter and cheaper than steel and aluminium.
Carbon is lighter than steel and aluminium but much more expensive.
I assumed you were talking about the frame, since you mentioned titanium and carbon fiber. Pedals out of those exist, but they're not exactly your run-of-the-mill materials, even on higher-end bikes. Honestly, carbon pedals sounds like a shitty idea. Controls pretty much stop at aluminum or even plastic in the case of shifters, since they don't take very big forces.
Carbon/Titanium pedals: https://www.lookcycle.com/fr-en/products/pedals/road/race/ke...
Basically all high-end pedals include some kind of titanium or carbon
Totally agree with this. eBikes are already too heavy for my tastes.
Having the motor means people don't care about things like slow rolling tyres, heavy finishing kit or the weight of the transmission to handle the extra torque.
That in turn means you need heavier brakes to stop.
Luckily not every bike has to be the same and we can pick and choose as needed. I'd rather have a lighter bike and have to service it once a year (if that) but that's just me.
Now that the edit window has passed, I realize that I have to add a correction or a caveat. I realized this when I added a drop of oil to my brakes. The car is "unreliable" too, but comes with expectations for periodic maintenance that replaces those parts. All fluids are unreliable. That might even deserve to be a law of engineering.
In fact, when I add up the time and money spent taking care of the periodic maintenance of my car, which involves driving it to the mechanic's, it's way more than what I would consider to be remotely acceptable for maintaining my bike.
I think that you got it right, expectations for cylcing are different. Even avid cyclists could never hit the kilometres travelled by your average car user in a year. Being a lot more expensive as well cars need to last longer for the cost benefit math to make sense. If your car broke every in 10,000kms you'd be livid, out of action constantly. If your bike breaks down, you can probably fix it that afternoon if not on the spot. Worst case you can probably walk it the rest of the trip.
That's where the e-bike is crossing barriers a bit. People will ride them much further, and getting the e-drivetrain repaired can be a real time and money sink. So you want it to be reliable, more reliable than the rest of your bike even.
> Even avid cyclists could never hit the kilometres travelled by your average car user in a year.
According to different sources, the average kilometers travelled by motorists are under 25k km/year (including Europe & US).
You'd be surprised by how many amateur cyclists ride more than that each year.
25000km is 250 100km days per year. That's a lot.
In France for example the average yearly distance travelled by car is closer to 12000km not 25000. More achievable but still a lot.
What a strange way of counting 25 k km ;) shouldn't you say 25000km or 24Mm?
25000km/year is ultracycling territory for amateur cyclist. Yes some people do it, a lot definitely not and I don't think many of them have a full time job.
I wrote first "25k" because that's how I usually write on other platforms, and then I remembered that I'm on a US website, so I felt the need to add a unit.
Sorry!
And if I had written 25000, I would have been afraid of people telling me that it should be 25,000 or 25 000
Thousand is frequently written as k or K, at least in polite society (metric).
you never say kk for one million though. k in km stands for 1000meters already.
Smoots
> You'd be surprised by how many amateur cyclists ride more than that each year.
You wouldn't.
As an 8k km/yr cyclist with a lot of cycling friends, I can tell you that 12.5k/yr is extremely high for an amateur. Sure, there are some, but a truly tiny proportion.
8k/year eats bikes, BTW. I used to wear out rims regularly before I switched to disks and chains/sprockets didn't even last a year (on a fixed gear bike).
First, this is what OP said:
> Even avid cyclists could never hit the kilometres travelled by your average car user in a year.
And you tell it yourself:
> Sure, there are some
So, if OP really thinks that no cyclist can ride more than what an average motorists drive a year, then even "but a truly tiny proportion" would appear as a surprise to them.
Also, just looking at my Strava right now, amongst the 30 friends that I follow (I'm picky on my follows), more than a third are on their way to ride more than 25k this year. The most advanced is going to reach 23k by the end of the day based on his current numbers and habbits.
How, where and when you ride your bike will be a huge factor in how much wear it gets. For instance, my commuter' chain usually get less than half the mileage that my road bike' chain get because city is dirty, I ride no matter the weather, don't clean the chain after each ride and keep putting strong torque since I constantly have to stop and start. Same goes for brake pads: when I commute I hardly do 200m without having to brake, whereas I can go for 20km without having to touch my brakes on my road bike.
> So, if OP really thinks that no cyclist can ride more than what an average motorists drive a year, then even "but a truly tiny proportion" would appear as a surprise to them.
I said an avid cyclist, which is quite undefined so fair enough. What I meant was an enthusiast still, not a sport rider or someone you could consider an amateur athlete (many road riders).
Road riding gets you a lot of KMs and hours in the saddle too, like you said in quite a specific wear pattern. I ride for hours on my MTB and my commuter but would never come close to the hours and KMs of road riding, and I will be replacing my MTB sprocket and brake pads much sooner than my commuter.
I think we're more or less on the same page though, and since all cities and cultures are a bit different we could be talking past eachother without specifics at which point my general comments go out the window anyway.
Yeah if you do mainly MTB, I can definitely see why we had a hard time understanding each other!
That's partly why when people talk to me about "how many km do you ride each year?" I respond in hours on the saddle.
Just for the sake of disclosure, and to provide one data point, I ride 8 miles per day, 5 days a week, year-round, on two bikes (summer and winter). That's about 2600 km/y. Maybe add a few hundred km for occasional weekend recreational rides, and getting around town.
People are quite careful with their cars. People are really not careful with bikes, including e-bikes.
I think that's a generalisation too far. :P
I don't care a hoot about my car, I wash it once a year whether it needs it or not.
It's the same for a commuting bike. My road bike on the other hand gets washed, tyres pumped, transmission cleaned and lubricated on every ride.
I think most club riders would be just the same.
It's not just vanity, dirty transmission is more tiring to pedal when you're trying to keep up with a group and when you're coming down hill at 50mph you want to know your brakes will work.
Tell my teenagers ;)
And look at the average railway station bike parking.
Bikes have it rough. They have crappy suspension, usually are used on roadways that are much worse than the ones that cars ride on, they have to regularly deal with impact and g-forces that you rarely see in cars outside of actual accidents and people drop them all the time. I've been working on bikes all my life and if there is a form of bike damage that I have not seen yet it would amaze me.
> And look at the average railway station bike parking.
Yeah there definitely seems to be a polarised dichotomy here.
Bikes are either very pampered or have a squeaky chain and gears that don't index properly with nothing in between!
>I wash it once a year whether it needs it or not.
I admire that, I used to wash my truck once a year too, until I ran out of time.
> There must still be a limit to how much size and weight a rider is willing to tolerate.
This is true for bikes, and after decades of marketing and fearmongering, basically the inverse is true for cars.
I'm saying this as a european non car-owner who's never been to the US, but my impression of car brain from over here is that anything that approaches light-weight is seen as a "death trap" by a majority of US drivers, especially because the rest of car users drive cars that literally have the size of WWI tanks.
My favourite are utes (Australia) / trucks (US) with a hard cover over the tray are.
Glorified shopping cart.
Might as well buy a hatchback.
Battery cells are generally binned like many ICs and the best cells go to cars and other high margin, high performance, or safety critical goods. The lower quality ones go to more cost conscious markets like the ebikes, where problems in quality control can definitely show up, especially if the OEM isn’t careful in how they spec the deliverables QA on the battery manufacturer’s side.
How are ebikes not in the high margin category? The Bosch batteries sell for €1000/kWh at the pack level.
I think it's the BMS, Batteries in cars usually get used between 20/80% and have active cooling and heating while ebikes don't.
High margin means stuff like aerospace, defense, and biotech - although a more accurate phrasing might have been “high value add”
How many cycles does the ebike battery go through in 200k+ miles? An EV car does ~300 miles/cycle. So 200k miles = 667 cycles.
Cycles is not the only variable in play here:
- Depth of Discharge - how often you go from full to low battery? Going twice from 80->30 (which accounts to a single cycle) is much better than single 100->0 cycle
- Thermal management - what are cell temperatures when battery is being charged? Maybe it is charged in direct sunlight? This will kill battery pretty fast. At what temperatures are the cells when driving the ebike?
- Ebike/scooter probably being charged to 100% more often than necessary.
- Did you leave your battery at winter completely discharged or fully charged in your garage? Bad.
TLDR: Info I gathered about reading how to take care of Lithium NMC batteries which are so widespread.
i get about 90km of range from a 500Wt Bosch battery. Thats running at full power the whole time.
With 600Wh battery and Shimano Steps E5000 in lowest support level I can easily ride 250km/charge
That is amazing performance. I usually get about half that.
I usually ride faster than the motors limit, so it's really just acting like a push, and most of the battery is spent dragging me up a really big hill i live on. Everywhere I ride down in town is pretty much flat.
Battery service life depends on many other factors besides just manufacturing quality: time, operating temperature, number of charge cycles, charging parameters, etc. On top of that, each cell design is optimized for some set of operating parameters: load, energy density, specific energy, price. It's all variables, so you'd have to narrow that question down quite a bit to even hope to have a reasonable answer.
They last about the same number of cycles, but a cycle on a car is 250-350 miles, a cycle on a typical ebike is 20-40 miles.
Ebike BMS will also drive the batteries harder (allowing to reach deeper empty/full states) since their design lifetimes are shorter than cars.
(Gouach co-founder here) Car-sized batteries last long because they have so much redundancy, that even when multiple cell fails, you barely notice it. It's very different in a smaller e-bike battery packing 40 or 80 cells.
Cells aside, cars have very good suspensions, and their batteries have been designed with very pricey component to eliminate shocks and vibrations.
On e-bikes, most batteries will have to sustain those, and we've seen a LOT of commercial batteries who were out of order for a simple $5 electronics component which was broken, and which couldn't be replaced because the battery was not made to be repaired (soldiering, glue, etc)
discharge rates
I imagine it’s partly due to bad quality control and engineering. No active cooling, probably a not well optimized battery management system. The batteries probably have more shock from lack of suspension.
On the user side folks may not be keeping them optimally charged.
There's a lot of noise around EVs between range anxiety, recycling, catching fire etc. Is this riding on non-existent problems or is it solving an actual real problem which I've been lucky to avoid so far?
I don't do e-bikes but I've had E-vespas and e-scooters and replacing a cell isn't really something I've had in mind. I've had lots of failures, none of them were from the battery. They all died too, before the battery.
The next step of the lifecycle is recycling, and that's done by professionals who do have arc welders, so they don't require such convenience
We're going to produce larger batteries for vespas, golf carts and scooters too!
Our repairable battery is actually quite convenient even for recyclers: many studies have shown that if you can get pristine cells, without all the casing / electronics / plastic parts as you're recycling the cells, you get back a much more pure recycled lithium at the end of the process!
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>> It keeps you updated on the status of cell performance and heat through a Bluetooth-connected app
why an app? Why not a simple light or error code on device?
There is both! But the app obviously has a few advantages in our setup:
- it gives much more detailed and fine-grained informations
- it allows user (optionally) to register for automated safety alerts
- but more importantly, it allows users to override themselves the communication protocol of the battery, to adapt it to any bike
For now we've hardcoded Bosch, Bafang, Brose and a few others (more coming), and we plan to open-source the communication protocol soon so that anyone can upload their own WASM code on the battery to talk to any controller!
1- might make the (waterproof) case harder to build 2- finding the right dead battery among 18650 batteries is requiring more hints than just "something is wrong" 3- marketing / convenience and probably you can order your dead battery straight from the app 4- monitoring battery charge, battery life / cycles / etc. 5- no idea :-)
Just speculating, but I guess there are a lot of reasons why a bluetooth app makes sense
I think the idea might be that you don't need to check the battery health yourself but instead you get pinged when a cell's getting close to dead
Your second point made me chuckle ;)
Why not both? I'd love an error LED to tell me something's wrong, maybe (maybe) with complicated blink codes that I can count and recount to determine which cell is bad or what action to take, but I also want a Bluetooth app to access the actual data: live cell voltages, currents and temperatures, estimated storage capacity and cell health, lifetime charge cycles and total power delivery... Give me all the data!
I don't want to increase the cost and complexity, and reduce the runtime of the thing with an onboard tiny LCD and an array of buttons to navigate menus. The interface could be available over a Bluetooth app, or or a self-hosted webpage, or make it show up as USB mass storage or a USB virtual serial port, or an actual RS232 or RS485 or TTL serial port, or I can grab it off a storage device with an EEPROM clip, or hook up my Tag-connect cable and a bus pirate and get I2C or SPI or whatever unnecessarily custom UART protocol you want to invent, or I can buy your dedicated HMI device with the LCD and buttons connected by a custom cable (don't want to buy yet another, I already have too many kicking around from decades of work with random industrial VFDs and PLCs and stuff), or I can hook up my MSO to some test pads and read the signals directly... But not everyone has all those tools and cables.
Like it or not, the standard has become a Bluetooth app. I wish the standard was a self-hosted webpage, so I could connect my laptop to a buried RJ45 connector, set a static IP to point my NIC at the right subnet (or the device could embed a router to assign my laptop a compatible IP over DHCP, but most don't), or I could turn on an integrated wifi adapter in the device, ignore and revert the protestations of my device and OS that the connection was unsuccessful because it can't ping connectivitycheck.android.com or captive.apple.com or msftconnecttest.com or whatever through the battery pack SSID. But by the time your user manual tells the user to go to their network adapter properties and set their IP address to 10.10.0.2 (on their iPad, LOL) you've lost most people long ago.
Like it or not, the standard has become Bluetooth and an app, and not without compelling if frustrating reasons.
You can't see what cells are low or have high IR with just a light on the device easily.
Maybe a small screen on the device would work, since it has replaceable cells you do need to know more details about which cells are weak.
Bluetooth connect apps are pretty much commodified at this point.
If one product has an app, and the next one doesn’t, people will choose the one that does.
so long as the protocol is simple enough to be recreated in nRF Connect, Bluetooth is fine. A proprietary bluetooth connection would be gross, though.
It would be cool to see a fully open source ebike. Sort of like a framework (the hardware company) of ebikes.
We're only working on the battery, but we plan to open-source at least the app and make the communication protocol extensible with "plugins", in order to let users configure their batteries for any controller protocol!
What would you like to see beyond what you can already do, i.e. buy a bike (or frameset, wheelset, groupset) and conversion kit?
I think the proposition is an open-source "conversion kit". Battery, charge controller, motor controller, sensors, display, source-code, specifications, etc. Built with some sort of standard so parts are easy to swap/extend. I like the idea
Like it's mentioned in the article the motor controllers themselves are closed source so they have to hack the protocol in order to plug the battery into it.
What if all the software and hardware systems of the bike were open source, not just the battery.
Great idea! I try to buy devices based on 18650. It should be the new AA standard, right?
But the so called 'USB' 18650 torch I got has a custom magnetic charger, yuk!
The last 3 hand-held vacuum cleaners are 4x18650, but have all been welded, and non replaceable.
Bike battery is already flagging, but newer replacement design has different connector.
Having a universal bike battery like this sounds perfect!
Even better if they make it into a generic power bank design; 48V would be perfect for connecting to solar panel for charge, then use it on the bike, lawnmower, laptop, maybe a small 230V inverter add-on.
Or a smaller 8/12 bank for pushing back against power tool company 'lets change the battery standard' every 2 years so that we can sell the same tools again.
Nice to see some attempt to fight this locked-down throw-away manufacturing obsession. Well done!
(Gouach co-founder) Thanks for your comment! That's exactly what we're trying to do, giving back power to people by providing them stuff that they truly own, they know how it works, they can assemble and repair them (or ask their local bike-shop to do it) without any vendor lock-in!
> Even better if they make it into a generic power bank design; 48V would be perfect for connecting to solar panel for charge, then use it on the bike, lawnmower, laptop, maybe a small 230V inverter add-on.
Great idea, I would love to see them offer solar chargers as well.
I was thinking of designing an open source UPS at some point, I guess I could architect it around this battery (though LiFePo would make more sense). I will have a look at the docs when they are out, I hope there's a communication/diagnosis bus, though Bluetooth would work as well.
Nice. I think I saw mention of support for custom WASM plugins somewhere.
From a device manufacturer's perspective, it is mainly a safety and reliability issue.
The form factor might be (mostly) standardized, but the cells themselves are not. There's a huge amount of variation between them, and using a cell improperly can quickly lead to some very nasty fires.
This means user-replaceable bare cells go right out the window, and you're left having to build a custom protection circuit for the cells you want to use - which means you essentially end up with custom batteries.
The solution might be a standardized way for the cell to communicate its health and capabilities to the device using it - but good luck getting the industry to adopt it. It provides no immediate benefit to the consumer while making the product more expensive, so they'll only do that when the government forces them to.
I like the idea of Batteries as a Service, and I could see it working in some US cities for scooters.
https://www.gogoro.com/
Many consumers just don't want to worry about battery health. Reportedly, battery degradation anxiety is driving down used EV prices in the US.
(Gouach co-founder here) A lot of people would prefer to not have to care, but many of them do care because they know it's the major "consumable" part of their $3000+ e-bike investment, and they want to know if it will last long, if it's robust, and if it can be repaired in case it's needed
Additionally, we've seen more and more customers wary of the environmental and social cost (children mines, etc) linked to lithium batteries, and who are looking for more durable solutions
In China they have car battery swap stations. For such batteries, owenership does not make much sense, so a subscription model indeed seems logical. The monthly fee covers the cost it takes for the company to replace worn cells; electricity could be charged separately for cars. For scooters, since the batteries are easy to swap yourself, buying and swapping a new battery is not that big of a deal, so I don't see subscriptions working as well there as for cars.
(Gouach co-founder) Yes! Our battery would be perfect for a swap business, they could easily fix damaged batteries, repair cells (only $50, instead of buying a new battery at $300 retailer price), and at the end, they could even retrieve used cells to sell them back for energy storage applications!
Gogoro is a borderline scam.
There are not multiple battery providers. You can only get batteries through gogoro and they dictate the price (it govt fixed for X amount of year and then who knows what happensl. Till recently you couldn't charge the scooter/batteries at home (even now it's made impractical)
You in effect are renting your vehicle
It's only successful in Taiwan due to slick marketing and intense nationalism
I think it is a pretty god idea. It may remove quite a bit of battery waste.
it's a cool idea for small setups, but very expensive per kwh.
if you want the same kind of style diy-er box-for-batteries I suggest the Trampa offerings. Similar focus on safety and novice level DIYer capability but much larger capacities and arrangements.
Very nice battery boxes! Our product is expected to go down in price as we increase the production.
Our product also comes with a high-end connected Battery Management System (the "brain" of the battery), and with a sturdy and fire-resistant aluminum casing!
I wonder if this will allow flying with an ebike battery in disassembled form. The regulations allow up to 100Wh per battery, and an unlimited number of batteries, so transporting the individual cells should be okay, at least in theory.
Lugging an entire suitcase full of 1 kWh worth of batteries might not technically be against regulations, but I imagine you'd be signing yourself up for a long series of headaches at the security checkpoint anyway. To be honest, if I knew that security wouldn't stop me because "it's not technically against regulations", that's exactly what I would do if I wanted to bring down a plane.
Right, that's basically the problem, if one wants to travel by air with an ebike without hassle, there's no real option to do so.
There's the Ligo 10X (https://ebikes.ca/product-info/grin-products/ligo10x-battery...) which makes 99Wh battery packs that can be connected together, but otherwise it just seems like rules lawyering.
There really needs to be standardization of battery packs for ebikes instead of proprietary ones, so that one could rent a battery at their destination.
At that point why not just rent the whole bike and not need to bring the large object onto the plane?
Because ones bike is a carefully selected item perfectly fitted to ones body shape and preferences, whereas the battery is simply a line replaceable unit.
That's such an edge case though.... what about my fine tuned piano? Or my aquarium? At some point personal luxuries don't have to be accommodated for
Even as an avid cyclist who fully understands geometry and the personal connection one may have to one's bike, I agree with you.
Privileged enough to fly somewhere specifically to ride bicycles? C'mon, I think you can find a good enough bike to rent when you get there.
Absolutely you can. The places in France and Spain I've flown to just suggest you bring your own pedals, so they match your shoe cleats; they'll fit them before your hire. You can usually bring your own saddle too. It's far more convenient than bringing the bike.
I've also done it the other way, my main bike has S&S coupling so I could bring it aboard the Eurostar. For touring I prefer my own bike, because I have the racks set up for my panniers, but when I do that, I prefer travelling by ferry/train.
I love it! Even for the lift/shuttling-bike-park crowd, I bet many places would happily install cleat-matching pedals (or your own), your saddle... maybe your grips if you are picky?
I think the intersection between people who ride e-bikes and cyclists who obsess about bike fit is fairly small.
You totally have the option to fly with a regular muscular powered bike.
(Gouach co-founder here) Yes! that's a possibility in theory. You can just remove all the cells, which then become "inert", and the pack set aside. It then only takes 5 min to reassemble them at your arrival.
I would honestly not want to fly on a plane with this or anyone else's ebike batteries. To dangerous.
You don't even want to be in an elevator with them. There are some absolutely horrific videos of how quickly this can get out of hand.
An even bigger model for vans (to get 2 kWh) would be great. But electronics for 48V is still rare and expensive.
Would this be possible in 12V ?
Can we also put LiFePO4 instead of Li-ion ?
We are working on larger models already, and we plan on models for LiFePO indeed!
Subscribe to our newsletter if you want to be informed :) https://gouach.com
Merci !
An ebike is very weight sensitive. How much extra weight does this innovation lead to?
I would rather have the whole battery be replacable. And when you want to replace, you trade-in your old one for a discount on the new one.
> An ebike is very weight sensitive.
E-bikes tend to be quite heavy, and many of them have designs that are very much not optimized for weight.
> I would rather have the whole battery be replacable.
They are. And the replacements are single-source and are very expensive.
To a degree yes, however I have an ebike and the bosch battery with a it has a 500W battery which is about equiv (if my math is right) to a 28 Ah ryobi drill battery. Those don't exist btw, but if i wanted one and bought 7 4Ah batteries to get the same effect they would cost more than the single ebike battery.
As a single item they are pretty well priced for the power they offer.
I think those batteries have their own BMSs, plus casing etc, that adds to the cost. The story as I can understand it is about being able to swap out individual cells which won't have those overheads.
(Gouach co-founder here) Thanks for your question! You can see the exact specs on the Gouach website here https://gouach.com/products/infinite-battery-complete-kit?va...
The battery itself is 3.3kg, so quite comparable to other models, keep in mind it comes with a sturdy aluminum casing.
What we mean by "replacing" is that you can change the cells of the battery yourself (or by asking at your local bike shop), so you don't need to trade-in the whole battery! This makes you gain time and a lot of money!
Thanks for the answer. 3.3kg is quite light.
Pedal powered bikes are very weight sensitive. The average e-bike (at least one that would use a fat battery pack like the on pictured in the article), are less weight sensitive.
The RadKick 7 (which RadPower calls a "lightweight bike" weighs 55 lbs.
Racing bikes like the $10K Trek Domaine Carbon weighs less than 30 lbs, but has a much slimmer (and lower capacity) battery pack than what Gouach seems to be targeting.
This page says the Domane+ (the one with battery assist) weighs closer to 40lb:https://www.trekbikes.com/ca/en_CA/domane-plus-faq/
I don't like their product naming -- they use the same name for different product lines.
The Domane I was talking about is the SLR carbon series, it ranges from 28.3 lbs for the SLR6 ($9K) to 26.1 lbs for the SLR 9 ($17K)
The Domane+ ALR is the Aluminum framed series and is heavier, but their specs page says it's 31.73 lbs for the ALR 5 (ML frame size).
https://www.trekbikes.com/ca/en_CA/bikes/electric-bikes/elec...
https://www.trekbikes.com/ca/en_CA/bikes/road-bikes/performa...
Very little I'd bet and location of the weight is far more critical to overall utility. Hopefully this is well thought out.
This is a great idea. Would be wild if they could support switching on the fly between 32 and 48v for a range/speed option. That gets complicated though.
Most e-bike providers will buy their switching logic based on the voltage in use, a driver for 48V would be substantially more expensive than one for 32V. There is also the whole charger setup to consider so yes, that gets complicated.
Doesn't need to. Power is power.
This guy is right, the premise of switching doesn’t make sense, power is power.
I only remember when I built my own batteries, I would get more range at lower volts because at about 40+km/hr you end up pushing wind and range goes way down. So yeah, technically power is power, but it's fun to go 50km/hr if you don't have far to go.
There probably aren't many EVs that can't regulate voltage across motor poles between 0 to +battery pack(or -1/2 to +1/2 pack) voltage...
Did your controller only have one power setting?
Yeah it did. It was fairly burly to begin with and I modified it with a stronger mossfett. This was back in 2007 when ebikes were very fringe. I would get packs of defective DeWalt drill batteries on eBay to harvest the good cells and build my own packs. I spent almost as much time building the bike as I did riding it. Ebikes.ca and endless sphere forums were full of help.
Cue Bob Parr meme...
Changing the voltage doesn’t change the amount of power being used, the only thing that would change is the ampacity (which only impacts conductor size, in this case).
480 watts == 10 amps @ 48V == 15 amps @ 32V
An electrically commutated motor (brushless DC) in an e-bike will almost certainly have a speed controllee, if you want more range you simply have to go slower ;)
Reconfiguring a battery pack with the same number of cells doesn't change the power contained in the pack. However lowering the voltage will lower your top speed (if not already artificially limited by the controller) and raising the ampacity of the pack may allow you to get more torque from the motor if you haven't saturated the motor and you change the controller settings to pull more amps from the battery.
Ah yes, DC motor speed is controlled by voltage. Glad to see Cunningham’s Law still holds true, thanks :)
I’m much more familiar with three-phase AC induction motors from my day job and the speed on those are (most commonly) controlled by adjusting the frequency with a variable frequency drive while maintaining the same voltage instead of directly controlling the voltage like on a DC motor.
Yeah but the wind kills range much more so at the higher speed 48v gives you and you tend to never run at half throttle.
Balancing will be a nightmare I guess, or just dont do it. Nice idea for the advanced user but I would not let my parents fiddle around with lose 18650 cells for the sake of their house burning down.
I see a niche application but personally hope they get it to market and make it compatible with Shimano. My double sized battery is a frankenbattery: pcb from original with custom printed case fitting onto the original attachment device using the batteries from two original batteries. Measured and balanced of course. Safety is "meh" I guess because DIY. I'd like to replace it with something more properly designed.
I did my masters thesis on how to balance batteries with very little information on each individual battery a-priori! Unfortunately I didn’t get to do experimental stuff because it was the middle of Covid, I only had simulation data. You can do some interesting things, though I wonder how many issues we missed/avoided by working only in simulation.
Edit: here’s the publication if you’re curious: https://www.sciencedirect.com/science/article/pii/S240589632...
Edit-edit: wow I got two citations!!! Never thought anyone would read my paper, that’s amazing.
Can I put that into a humanoid
This is such a terrible idea because the packs have to be factory balanced before assembly, and everyday Joe doesn’t have the equipment (or probably the understanding) to do this part properly.
If the packs are not perfectly balanced, the batteries just short into each other and explode, and BMS can’t do anything because there isn’t any per-cell switch (cost).
It’s not just a matter of balancing voltage either, the cell profiles (voltage vs SOC) have to be the same otherwise you end up with 1 cell doing all the work. Simply put, when you mix and match cells of different brands, models, or even ages, they don’t integrate evenly. This results in a few or even just 1 cell doing a majority of the work during both charge and discharge, maybe 10x higher than its safety rating, guaranteed fire…
Also end-user is expected to do the math and input the battery’s total current rating into the motor controller? Yeah, nah, a hundred kids will think it’s cool to set this too high and set themselves and people around them on fire.
The cells which are in parallel will auto-balance when inserted. It's true that putting an empty cell and a full cell in, can indeed lead to a unextinguishble fire due to thermal runaway. But from the factory, cells will be very close already. They will auto balance once inserted (the parallell cells). Every single charger in existence will then balance the series cells actively on every charge cycle. So "terrible idea"? No, but maybe something to leave to the bike shop. Still better than throwing away the pack. And maybe fuses between every cell would help for protection against
(Gouach co-founder here) Exactly! The first kits are DIY for our early adopters, but we are working on an assembly pipeline in France, China and the US for our models in the coming months. Clients (B2C and B2B) will receive pre-assembled batteries
We are also looking for bike-shop owners who want to train on our batteries (it can be learned in one hour or so) to get a new revenue stream by offering to repair and assemble our batteries!
Seems an overly pessimistic take. TFA specifically mentions per-cell temperature monitoring, and I would assume there is also per-cell voltage monitors.
As long as the controller is made sufficiently conservative, there is no fundamental problem: you limit the current according to the cell that heats the fastest and shut down once one cell is near depletion.
Maybe they have even gone a more aggressive route and build a balancing circuit that can route significant current around a low-capacity cell. Or maybe just charging logic to keep as many cells as possible in the 20-80 regime if they will be limited by low-capacity members anyway. There are so many options here.
The Toyota Prius community already has a better solution for this - You can buy remanufactured batteries, then send your used battery back to get a credit. ChrisFix on YouTube has a swap guide for DIYers - it's mostly taking all the interior panels out of the back of the car.
(Gouach co-founder here) This is nice, but when you have an e-bike with a malfunctioning battery that you use for work everyday, you don't want to have the 2/3 months it generally takes for exchange programs.
Plus, once you sent your battery, they either discard it which is not ideal for the environment, or try to remanufacture it, which is very dangerous when it's done on a battery which wasn't designed for it, like ours
Sounds like a challenge: start monitoring individual temperatures, long term recording of performance down to the cell, recommend a mAh value of cell in a particular location, dynamic ohm chips in series with batteries to control differential discharging.
I am not enough of an expert to know if all this could work, but its got to be better than replacing an entire pack at a time to be worth trying
Cells in parallel will stay balanced and act as one big cell even if they're different capacities although they do need to be the same voltage first, but in series they need to be matched in capacity.
Slight mismatches in capacity can be OK in series too, as long as you have a BMS watching the cell voltages to make sure none get too low when discharging and none get too high when charging. The risk is that the lower capacity cells get too low or too high while the overall pack voltage seems fine, causing dendrites to form inside those cells, leading to a short and a scary fire. It really comes down to how well the BMS is designed / programmed and how much you want to trust it.
Most people aren't aware of how dangerous it is to try to "revive" a cell that got too low so this technology definitely comes with significant risks for user error.
It doesn’t magically morph into one big battery, suppose you have 5 different batteries in parallel, 1 new and 4 used different model, and you discharge this assembly at 50A: a large proportion of the current will flow through the lowest IR cell, say 45A of it. But the problem is that cell is only rated for 10A.
So yes, the net current is supposed to be okay, but it’s not, and rather than responding individually to all the other comments I may as well mention that no amount of temperature monitoring will fix this. Temperature sensors don’t detect internal cell stresses that cause spontaneous failures.
Unless they're wildly different chemistries, they'll have an IR that's inversely proportional to SoC and capacity, so you won't get that situation of 1 cell supplying 90% of the current unless it also has 90% of the capacity of the pack. Any cell that discharges a little more will have its IR increase, reducing its share of the current.
(Gouach co-founder here) Most of our users buy brand new cells, and we are working with partners who do have the equipment to retrieve second-life cells and match them in their factories, before selling them as "matched second-life cells packs" back to users for a huge discount :)
Do you honestly think they haven’t thought of that/tried it out?
Let's hope the inane DMCA laws don't get them for decrypting the Bosch battery-motor communication.
If HN had profile pictures, mine would be a Clippy.
I wonder how much they will have to protect against recklessness of the e-bike owners? For example, against the end user sourcing substandard cells, and combining them in inadvisable ways.
I don't have a good profile of e-bike owner behavior about maintaining their own equipment, but what I can say is fewer than 1/5 of e-bikes will stop on red at a 3-way intersection near me (when cars are stopped in the parallel lane, and pedestrians are crossing).
We also see a lot of riding on sidewalks, at speed, to bypass red lights and traffic on a major street here.
That said, the e-bike riders are often wearing helmets as they plow through pedestrians, so maybe their recklessness only extends to the safety of others, and they'll be conscientious about not lighting a lithium battery fire between their own legs.