Indonesia's e-bike shops are building their own batteries | Hacker News Reader

Indonesia's e-bike shops are building their own batteries

restofworld.org

226 pointsdonohoe190 comments

Note that while the article says "soldering" the pictures show "welding", which is the typical way you create battery packs. The reasons are that the welding provides a higher temperature connection but for a shorter period of time, over all dumping less heat into the battery and potentially causing damage to the cell or triggering ignition. Also makes a higher temp connection, solder can melt when the joints get hot during use.

I got a battery welder a few years ago to repair an ebike pack and also to repair a EGO power tool battery pack, but thus far haven't used it. The ebike pack was a bunch of "packets" rather than 18650 cells, and the EGO was slightly smaller than 18650, so I need to wait for another pack to fail so I can scavenge cells from one to repair the other.

Be careful if it smells like birthday cake when you're working with lion cells, that can preclude them bursting into flames. Have a metal container nearby to drop them into for transport outdoors.

preclude: I think you mean that can be a prelude to. Though could also be presage.

I think I was going for "precedes".

Ah. That makes sense.

>Have a metal container nearby to drop them into for transport outdoors.

Before doing that, try watching some experiments with fireproof containers specifically designed for these fires, to have an idea how quick and violent this can be, and how bad most of these containers are at preventing it from going from 0 to inferno or to a toxic cloud suffocating you in seconds. This might or might not help you plan for the worst case, or better yet forget about doing DIY battery pack repairs at all.

> forget about doing DIY battery pack repairs at all.

Yah, some things it's best to not learn the hard way.

But if you're intent on doing it, to it outside on a concrete slab.

P.S. I do anything that involves fumes or dust outside, such as painting, solvents, etc.

What do people do in factories?

I'm skeptical of the idea that some repairs are meant to be performed only by "experts" and that nobody should ever try to learn how to make them. It fuels an industry of people charging hundreds or thousands of dollars per repair to install cheap parts, and it's part of the reason our society throws so much stuff away.

Sure lithium ion packs are dangerous, but there is a manufacturing process that: welds cells together to make banks, and that sometimes produces a runaway reaction inside the cells. Given that that's the case, it should be entirely possible to do that safely in a controlled environment inside of a garage.

This is the same attitude that informs our decision not to repair garage door springs. Or more relevantly the same attitude that tells us to just use whatever async library du jour exists but never to learn about the internals of that library. "Don't worry about what's under the hood, that's dangerous stuff" says the dealer's mechanic.

Do you perform your own dentistry?

Touche.

It's not the same thing because I don't have training to be a dentist, but I do have training and skills and knowledge for a variety of non-dentist mechanical, electrical, and electronic things. So this is a specious argument. Where does it end? Do I not do any work myself ever? Or are there things we can all agree some people are capable of doing?

I think the gatekeeping around all of this stuff from people is frankly kind of ridiculous. It's not like the battery repairmen are doing asbestos abatement naked in their living rooms while their families are watching TV. But people are treating it like the same thing.

Capability is fine but also goes hand in hand with risk. Working on lipo/li-ion cells is risky which is usually why such work is not zoned for residential areas. How would your skills and training translate into something a neighbor or inspector can understand? Would you resent them for questioning your non-dentist abilities? Is someone with no formal training but years of practical knowledge working on devices enough?

It seems like the questions from my end bend back toward proving yourself when a situation breaks, not when it works, which is what sometimes happens when you do work yourself. Have you heard the parable of the nuclear boy scout, David Hahn?

> I do have training and skills and knowledge for a variety of non-dentist mechanical, electrical, and electronic things.

A fundamental of expertise is knowing the terrain, what you can and can't do safely and reliably. A fundamental of knowledge is becoming aware of far more that you don't know; only in ignorance do we imagine there is little outside our personal boundaries.

Highly experienced professionals will tell me, 'I don't know how to do that, you should talk to ...', and will refuse to even venture advice. My doctor tells me to talk to a specialist. Naive, immature amatuers assure me they can do anything, and can diagnose and treat my medical condition via social media.

Don’t you? When there’s something wrong in your mouth, do you look in the mirror, use your tongue on it, use a toothbrush or floss or toothpick on the problem before going to see the dentist? Or do you feel pain in your mouth and magically you’re at the dentist without doing any of the above?

I don't bust out the drill or try to apply putty for a temporary tooth.

That is to say, yes, I can confidently exchange batteries (clean my teeth). I'm not confident in modifying those batteries with a welder/soldering iron.

If I clean my teeth and they still hurt you bet I'm going to the dentist.

For people who do this, it's more like changing batteries, than modifying them. You only put the batteries into the slots and attach metal wires to the ends - isn't that a lot like changing batteries already? The device which attaches the wires is simple to use: you press it against the connection, press the foot switch and it makes a little spark and now the wire is attached. If you know what you are doing, building a battery pack out of pre-fabricated cells is not scary.

Then what are they welding in the OP?

I don't see any pictures of welding happening in the OP. I do see a battery pack constructed with the usual spot-welded metal strips. The spot welder is the machine that you press against the connection, press the switch and it goes zap and you have a connection. It isn't especially dangerous, as far as I know. It uses a low-voltage high-current pulse to melt and fuse the metal only at the contact points.

Errors that may lead to a thermal runaway: Accidentally shorting a cell. Putting the cell in backwards. Putting a highly charged cell with discarded cells (or vica versa). Using a damaged cell. Any of these can happen rather easily, with potentially disastrous consequences to life and property.

Many things are dangerous. Use caution and have a backup plan (keep the area non-flammable and keep a bucket of sand nearby) and you'll be fine.

> Many things are dangerous.

That's not a rational response. Everything is dangerous. The issue is how dangerous they are.

Yes, sometimes, when it’s not convenient to utilize infrastructure where I am.

So far I have become adept at removing and replacing my own crown, including heavily modifying when needed, filling if they aren’t too deep (or temporary fillings if they are deep) and one extraction when I was at sea and had no better choice.

I don’t recommend it if it’s not necessary, but for those who may find themselves in that situation there is a book called “where there is no dentist” that outlines most common procedures and tool use. It’s worth learning if you’re likely to be away from “civilization “. Also “where there is no doctor “ can be a lifesaver.

You extracted your own tooth!? Woah. Speaking as someone who has seen people evacuated from Antarctica for dental issues, I'd like to read a blog post or something about that.

Of course, in such a case , you’ve likely waited (as I had) until the tooth is really bad. Despite antibiotics.

I think because of the infection it was quite loose, and prying a little with the elevator was all it took to get it to where it could pull it out with my fingers. If I had not had dental tools, it might have been much harder.

The pain is already really bad, yanking it out really wasn’t much worse than the steady state and once the nerves were severed it was instant reduction in discomfort.

Half a bottle of gin made it easier. The hard part was having to wait until the sea conditions were good enough that I felt like I could safely be numb-faced drunk.

Do trained dentists perform their own dentistry?

> What do people do in factories?

Ventilation. Compartmentalization. Controlled processes with early warnings. Proper tools. Quality control. Active fire suppression. Not doing that at home with your wife, kids, and your dog.

Sure, if you know what you're doing, can deal with thermal runaway, and can trust your work afterwards, nobody stops you from doing it. I've done it myself (never tried anything larger than a e-bike battery though). Just keep in mind that you're working with a firebomb that deceptively looks like an electronic device.

To add on to this, for most things the failure condition is that the thing doesn't work. Here the failure condition is a very high energy reaction and should be given the proper respect vis a vis safety.

Not an ideal analogy. A better analogy is "would you hire an electrician to do task XYZ?" Nothing stopping you from learning enough to do amateur electrician work -- but at a certain point, the risk to reward ratio becomes poor for most people and not a good investment. At a certain point, you're doing it to sate your curiosity -- not an invalid motivation by any means, but it's not necessarily driven by practicality.

You say that, but it sure was nice, last year when my dryer kept popping the breaker, for me to be able to easily track down that the electrician that replaced my panel ~8 years ago had (a) used the wrong breaker for the dryer, (b) used a physically damaged breaker, and (c) improperly torqued one of the legs leading to the dryer.

Learning DYI home maintenance is not for everyone, but I sure have enjoyed it. Being comfortable with so many aspects of my house is something I really like.

Breakers were design to be installed by the average Joe, as are drier legs. The failure mechanism of an improperly installed breaker is that it doesn't work properly, or it gracefully melts in a metal box which is required by law/code to handle that exact case of graceful melting and small plastic fires.

The tools and technique required for dealing with stack of little fire bombs, that explode if poked, bent, or overheated, sometimes at a much later date, while sitting in your garage/living room, has a much more serious failure mechanism. And, more than that, most DIY battery packs I've seen involve lack of funds and Aliexpress cells. In the RC hobby community, everyone knows that you store DIY battery packs, especially those made with cheap Aliexpress cells, somewhere where they're free to spontaneously combust without consequence.

Battery packs are scary. People who understand that have better outcomes [1] than people who don't [2] (tbf, these are Lipo)

[1] https://www.reddit.com/r/fpv/comments/fb1u4d/thanks_reddit_y...

[2] https://www.reddit.com/r/fpv/comments/l1hegi/psa_dont_leave_...

Why yes, I do all my own electrical. Has saved me thousands and I am more careful about many parts of the process.

When there’s actually dangerous stuff under the hood, maybe we should worry about it though. If piercing a cell with a screwdriver is going to cause a fire, and a runaway chain reaction could burn down your garage, maybe we should have a way to give mandatory training on how to handle things safely before you’re allowed to play under the hood.

Why is the cost greater than the benefit?

Because humans are bad at statistics, and don’t want to waste money on hypotheticals. “It’ll never happen to me.” So you can skimp on the cost of safety training.

'under the hood' is relative...

Most vehicles are Skateboard platform anyway; I feel like you'd already have to be in at least a semi-specialized shop to even get to where you can safely FAFO with the pack...

And frankly if a normal person manages to just 'get one' and put it in their garage well I don't know what to say aside from 'sometimes natural selection has factors'...

I’d rather we be able to teach people so they’re safe when they experience the FO part of thermal runaway. Hey, I really needed that bucket of sand.

But I don’t control what other people are doing, so, like you said, natural selection. The problem comes when that garage is adjacent to the neighbors garage, and it catches from there, that we do need to control what other people are doing.

Also, what do people do in RVs in the desert?

What people should do is not have flammable batteries in a vehicle unless the whole system, the entire RV or EV, has been designed by experts. I built custom designed safe solar starlink campers as whole systems and make physics simulations and do extensive tests. That is how you prevent most battery fire in a car or off-grid tiny house in a desert.

Ok how about a gas powered RV, a highschool chemistry teacher, and one of his former students, Jesse. I think that's enough expertise.

> I'm skeptical of the idea that some repairs are meant to be performed only by "experts"

If you're skeptical of this very banal notion than you are likely not qualified to be doing whatever work you're doing. Yes, tons of technology is needlessly complicated and the salesmen and their compatriots in the "no user serviceable parts inside" sticker division have spent a lot of time and effort to convince people that the inside of electronic devices is sacrosanct; however that has led to an IMHO dangerous notion that every instance of someone saying "hey, you really shouldn't take this apart on your home bench" is regarded with suspicion, or some notion of "they just want you to buy a new one!" and not that, sometimes things break and if they're designed well, they may well have a failure mode that prevents a much worse failure mode.

And it might be expertise that's the dividing line, but it could just as easily be a matter of the material itself: that sometimes, what's in there is pretty fucking dangerous actually and shouldn't be messed with by just any old guy, even a technical guy, who has a YouTube tutorial. It might be that the parts inside failed for a reason and replacing them, while it makes whatever thing work again, might not actually be a great idea depending on why the original ones failed and that if you don't know the answer to that question, blindly putting them back might be setting you up for something disastrous.

I'm 100% a believer in the right to repair, but I do not mean for that always to be myself. On the rare occasion I take something apart with lithium cells inside (which I avoid at all costs!), I handle them like live grenades and either re-connect them to whatever managing circuitry or, if whatever it is is beyond fixing, disposing of them safely. I don't do this because I don't understand them: I know intimately how they work. I do this because I understand them and respect the danger they pose, not unlike firearms or the parts of my car that I know I don't know enough and am not qualified to fix.

Being intelligent is, IMO, oftentimes more about knowing what you don't know and respecting that than knowing what you know.

And, as an aside just because it's related to this point I've articulated: do not take apart lithium batteries in an apartment. I don't give a shit what your qualifications are or how good your risk assessment might be, you do not have the right to take into your hands the safety of yourself and at the same time, every other person currently occupying the structure you inhabit. That is just not your risk to accept, full stop. You are not an island and all the high minded libertarian nonsense you can muster cannot get around the fact that if you make a mistake, no matter how benign in the moment, you could damn well set other people's homes on fire with zero warning for them.

> if you make a mistake

or if the battery is defective, or the power goes out and you're stuck in the dark, or ...

The flip-side of this is that there are so many activities that people do all the time that carry risk. Plenty of them are not really necessary, and create some risk for other people, and yet they are perfectly acceptable.

A good analogy is the use of candles. They are pointless and fundamentally dangerous, but some people like them. People who like them even think they are calming, which is a very bad reaction to an open flame from a risk-assessment point-of view.

If i knew my neighbour liked candles, i would hope that they are being safe and accept that they have a right to take socially-acceptable amounts of risk, not berate them on the internet.

I don't see how repairing battery-containing electronics is any different. Both are unnecessary, and both could turn a small mistake into a fire.

So, I'm quite happy replacing my own phone battery with reasonable precautions, but no, friend, you may not charge your sketchy e-bike in my hallway.

The level of risk that is acceptable is socially defined, and far from the black-and-white view that some people seem to have.

> So, I'm quite happy replacing my own phone battery with reasonable precautions, but no, friend, you may not charge your sketchy e-bike in my hallway.

Having myself witnessed a cell phone's battery go up when it was nicked during a removal, I'll take the candle a thousand times over one of those. But you know what you know.

Personally I just wouldn't fuck with re-manufactured batteries at all. Batteries should be new, from licensed factories, and they should be recycled in a way akin to car batteries so we don't lose all the lithium inside that's still perfectly good for another go-round in a new battery.

Yeah, i know the risk, that was my point. Given the difference in frequency (say, ~every day vs. ~once a year) and level of attention, the risk to others is at least comparable.

Given how popular DIY phone battery replacement is, you'd expect there to be at least a few incidents reported if it was a major risk, but I just don't see them. On the other hand london fire brigade reports 200 candle fires a year...

> Being intelligent is, IMO, oftentimes more about knowing what you don't know and respecting that than knowing what you know.

Someone once said 'INT is knowing how to make an Atomic bomb. WIS is knowing the implications of actual use'

> I'm skeptical of the idea that some repairs are meant to be performed only by "experts" and that nobody should ever try to learn how to make them.

That is a very dangerous point of view. Many things really are too dangerous and require too much expertise for you to do. That's how and why expertise exists - it's required to accomplish certain tasks. Not everything - not nearly everything - can be done by amatuers.

It's dangerous to you and also to people around you. The flaming lithium ion cell can kill lots of other people, or leave them in horrible pain and permanently disfigured with burns, or destroy lifetimes of memory and property.

What will you tell them? 'I thought I could do it'? Why did you try when everyone told you it was too dangerous? '...'

> there is a manufacturing process that: welds cells together to make banks, and that sometimes produces a runaway reaction inside the cells. Given that that's the case, it should be entirely possible to do that safely in a controlled environment inside of a garage.

Not unless you have millions of dollars invested in design (by experts trained and experienced in designing such facilities), equipment, and construction for your garage. And it's not near any neighbors - they don't put those factories in residential neighborhoods.

There are a few points to make here:

1) You need to understand how things work culturally in a country/region. SE Asia in particular does not have the same concept of mandated safety like in the US or the EU. Which makes things easy.

2) People need to stop using "domain expertise" to gate-keep other people from doing something. Yeah, batteries can be dangerous, but that does not mean you need a highly qualified and expensive person to do something trivial, like welding batteries together. If we would have gone down this path, not Intel/Apple/Google would have been born because Fairchild semiconductor had the expertise, IBM was making personal computers and everyone used Yahoo or AltaVista for search, so what would people without experience achieve, right?

When there are no alternatives or they are more expensive than DYI, DYI will always win in places like this. Do you think in Indonesia people have thousands of dollars to buy batteries like they do in other regions?

Computer boards might burn but it's usually just a nuisance. Not so much for high energy batteries...

This is not as big of problem there as it might be in other places. Here, a video of how fuel is transported in other parts of the world (popped randomly on my feed): https://vm.tiktok.com/ZGePEvYU5/. It gets the job done, everything else matters very little to not at all.

Dead people, or living people with serious burns and lifelong disfigurement, or property loss - that "matters very little to not at all"?

If those things don't matter, what does? Batteries?

In a lot of cultures people would rather die trying to save their house. And in many places, for example, people would rather die trying to get their luggage from an airplane in flames thn just running for their lives.

My point being that you should not see everything through “western” eyes where life is valued more over psysical possesions.

And to answer your question: yes, cheaper batteries matter more in Indonesia than “safe” batteries. And I am pretty sure the same holds for pretty much all of SE Asia.

The talking point for every evil is to try paint any moral value as arbitrary and/or 'western'. It's transparently ridiculous on a rational level, and furthers real evil, real harm to real people.

If you find yourself on that side of the debate, on that path, you've lost your way; you've followed the wrong people.

If you actually think commercially available battery packs are being produced in super high tech, super safe, quality-controlled factories by experts, you should try disassembling one.

You do not need millions of dollars of equipment to solder battery cells together. You probably need “expert” training, meaning, like, watching a YouTube video. This stuff is not complicated.

> You do not need millions of dollars of equipment to solder battery cells together.

I have disassembled several. They're all welded, not soldered.

Soldering will damage the cell. Improper welding will poke holes in the cell.

It's not rocket science but as your own comment proves, basic research is required as well as some practice welding it a safe location.

I didn’t know soldering vs welding could damage cells, thanks for that! The battery packs I’ve built are all made from cells that have threaded terminal posts, because I don’t have a laser welder (which as I understand it is the tool that gets used for this most often).

I stand by my point though, because a laser welder is not particularly expensive or exotic equipment, you can safely operate one in a garage, and you can learn to use one effectively with a little bit of practice.

Attitudes like “IT’S DANGEROUS DON’T EVEN TRY IT” are silly, and lead to people having unwarranted fear about really basic, easy-to-understand technology.

I design big custom battery packs in car trailers or shipping containers for storing them outside of infrastructure. If the battery catches fire you can drag the trailer or shipping containers further away to let it burn out. Of course it gets harder to drag them away after a few minutes of fire when the axles and wheels start to melt.

The point is to never put Lithium-ion batteries inside buildings, especially not put them inside heavy (metal) boxes bolted to the building.

> The point is to never put Lithium-ion batteries inside buildings

Missing word?

Because I have dozens of 'em inside this building right now...

> never put Lithium-ion batteries inside buildings

No EVs in garages or multi-storey car parks?

You will have to do some research to find out what the new laws in the making and fire department procedures say about garages and multi-story car parks in 2024.

A quick review by me just now suggests the government regulations still have not yet caught up with the new reality in the US and EU:

EV's and large batteries inside buildings are not yet forbidden but probably will be soon.

Fire departments choose to evacuate a building with EV fires (and other industrial fires) and just let it burn out [2].

Fire departments only quench a fire by sudden rapid cooling if possible, for example by drowning [1] the entire Li-ion fire in a basin. Taking the oxygen away is not the goal.

[1] https://www.ctif.org/sites/default/files/2023-03/Putting%20o...

I design neighbourhood batteries as two shipping containers underground. In the bottom container the batteries with multiple infrared camera's looking at all battery sides and also with redundant temperature sensors. The top shipping container will deliver 60.000 liter of water into the bottom container in seconds. Testing such a setup would make for a hot and cool spectacular Mythbusters episode.

[2] https://www.youtube.com/watch?v=MT1QTPEZoHY

> Testing such a setup would ...

You've tested it, right?

I wish, it'll cost a million dollars or more to test at this scale and it would still be one data point. Instead I simulated these systems to test the physics.

But please, come help me do this test in real life, it will be fun!

You can sell tickets to the events like it's 1930

Are you representing these devices to others as safe, with safety mechanisms? That is, are you selling or even giving them to people?

I hope only you are at risk from these devices (and I hope you are safe too, but that's your choice). Untested technology can't be depended on. As a rule I don't believe anything works unless I see it with my own eyes - if I swap in a new patch cable, I ping something. Safety equipment for mortal risks is on a different level.

Sounds like a sound design to me. If he gets sued at least he can argue he did everything reasonable to prevent and quench a battery fire. That's how gen 4 nuclear power stations are designed to cool the core in the event of a loss of coolant incident. The other way is to use LiFePo chemistry which doesn't ignite like LiIon but has half the capacity.

> Sounds like a sound design to me. If he gets sued at least he can argue he did everything reasonable to prevent and quench a battery fire. That's how gen 4 nuclear power stations are designed to cool the core in the event of a loss of coolant incident.

"Sounds like a sound design" isn't sufficient engineering; doing everything reasonable would include testing or using an existing tested design; and nuclear power station designs certainly are tested.

EV's and large batteries inside buildings are not yet forbidden but probably will be soon.

I'd like to see a reference for that, the closest I can find is this NFPA bulletin calling for updating fire protection and electrical standards for parking garages, nothing suggesting a ban.

https://www.nfpa.org/news-blogs-and-articles/blogs/2022/11/2...

https://risklogic.com/evolving-fire-safety-recommendations-f...

> EV's and large batteries inside buildings are not yet forbidden but probably will be soon.

Really? That would more than inconvenience millions of people who already have such things. Seems most unlikely to me. Here in Norway we have about half a million EVs many of which are parked in private garages overnight and in multistorey car parks during the day. I can't recall a single incident where the battery either caused or exacerbated a problem.

EVblog 1422 - CAUSE of the Tesla Victoria Big Battery Fire https://www.youtube.com/watch?v=oknr1OaqnUE&t=1178s

Report: https://cityfire.com/wp-content/uploads/2024/01/VBB_Statemen...

The conclusion is very encouraging!

> The affected Megapacks failed safely despite total loss.

>Before doing that, try watching some experiments with fireproof containers specifically designed for these fires

I watched a bunch of those videos on YouTube when I was in the market for one and ended up not buying any. The ones that were fully sealed just exploded and the ones that were vented shot 3 foot tall flames and showers of sparks out of the vents igniting everything on the ground around the container. Better to just charge the bike outside on pavement or concrete away from anything flammable.

> Note that while the article says "soldering" the pictures show "welding",

In some languages, these are the same word (this is the case at least for my native Portuguese), so this could just be a translation issue.

Wait what? Is there a distinction for Brazing? There isn't a distinction for the same metals vs different ones?

How about glueing? After all, two parts are held together by application of a different substance.

They're also more or less synonymous in Chinese, resulting in a lot of weird phrases like "infrared welding" or "SMT welding practice kit".

Interesting: How do you express the difference between soldering and welding?

Welding melts the metal to be joined, and joins it with a fillet of the same material.

Soldering does not melt the parts to be joined, it just melts the solder, at a much lower temperature.

Brazing is the midpoint of these: joining with dissimilar metal, without melting the parts to be joined, but at a relatively high temperature.

The GGP said the words for welding and soldering are the same in Portugese. I was asking how people express the difference in Portugese.

They're distinct in Indonesian, the former is "solder" while the latter is "las". Most likely a technical assumption made by the author during his visit to the workshop

> Be careful if it smells like birthday cake when you're working with lion cells

This is hilariously specific. I wasn't sure how to describe that sweet smell of li-ion packs immolating. Birthday cake seems to fit it perfectly.

Ah, Mom's good old lithium birthday cakes ...

The birthday cake smell thing is right on, happened to me. I was transporting a hobby fighting robot and noticed the smell. When I took it out of the metal box I found a wire had broken and the 18650 battery was shorted.

In addition to the heat issue, a lot of battery contacts don't form a good joint with typical electrical solder.

Source: Tried to solder batteries.

Interesting. My father (retired engineer into these things) was talking about making a battery pack welder recently.

Something about it using a directed microwave pulse to make the weld spot, so it doesn't dump a bunch of heat into the batteries and potentially cause a fire.

The theory of it sounded ok to my layman ears. Hopefully he gets it up and working in the near future. :)

I have no idea what the fascination with this is, and what makes these batteries "homemade".. also, it's spotwelding and not soldering.

Buying battery cells and spot welding them together is a thing that many companies do, even in the "western world", i know of at least three in my small eu country.

Before lithium, they did the same with NiMh and NiCd batteries.

You can also make them yourself at home, although it can get relatively dangerous if you don't know what you're doing... same as with replacing an outlet at home, but more of a fire damage instead of a shock risk, so definitely not for everyone, but with some basic precautions, can be done safely.

The bigger problem in the current times is, that device manufacturers fight hard against any kind of repair or DIY stuff, so sometimes just disconnecting the cells from the BMS (battery management system) makes it "reset" and fail the "authenticatioN" between the device and the BMS (which exists only to prevent repair). Companies know how to avoid that (via using a power supply to keep the board powered up), but attempting to DIY fix it (without knowing about the issue) makes you destroy the BMS.

Is this really a common practice outside of FutureMotion/OneWheel?

Bosch is known to pair their hardware such that you can’t replace a bad element, e.g. replace a bad Bosch battery with a 3rd party unit. The entire Bosch ebike hardware ecosystem is locked down and only approved dealers can repair.

It’s pretty common. They’re far from the first ones to have started that practice, which began in the 2000s. The concept of the battery management system (BMS) killing the pack for safety reasons came with modern BMS chips that can do state of health (SoH) measuring, along with state of charge (SoC) measuring.

Some laptop manufacturers do that... once you disconnect the voltage from the BMS, the BMS is efectively dead. If you know it, you can use a power supply to keep it energized, if not, tough luck. You can still buy a 3rd party battery to use with that laptop, but the original laptop cannot be "renewed" with new cells anymore.

They are even matching the internal resistance of the cells, I can't think of much more a professional manufacturer would be doing. As long as they are getting their cells from reputable sources (big if) I don't see anything wrong with a boutique battery industry for niche applications.

A professional manufacturer would not put any cell in series but instead would have a charger/discharger with voltage per cell, with current and temperature sensors as feedback loops. The danger of cells in series differs with the cell chemistries.

Using a BMS is another indication they are not professional or even had an engineer design them.

Sadly I know of only a very few small professional battery pack manufacturers, certainly none of the EV or bike makers.

> Using a BMS is another indication they are not professional or even had an engineer design them.

What is the proper alternative? Do any ebike packs conform to the standard you expect?

By "series" do you mean "parallel"?

Note that Tesla famously used a 6-series/74-parallel configuration in the Model S's battery pack: https://circuitdigest.com/article/tesla-model-s-battery-syst...

Each pack only had a single BMS connection for every clump of 74 cells! Presumably they only got away with doing this by doing extensive binning/characterization of the cells before building them into packs.

> A professional manufacturer would not put any cell in series but instead would have a charger/discharger with voltage per cell

My Bosch e-bike has 4 cells in parallel and put 10 of those in series. This so called 10S4P is a very typical setup for e-bikes. Each individual cell does definitely not have their own current/temp sensor. The BMS will check voltage for each of the 4 cell blocks.

> I can't think of much more a professional manufacturer would be doing

Safety equipment, in a safe environment, not exposing others to fire risk?

I would define "homemade" as assembling the batteries without any sort of regulation or safety standards.

I'd be a bit frightened if I knew someone in my apartment building was assembling their own batteries -- poor quality ones can burn down the building.

It's an increasing problem here in San Francisco. I know at least one friend who had to move due to smoke damage caused by a neighbor collecting these batteries. https://sfstandard.com/2024/01/09/san-francisco-e-scooter-bi...

Yeah this is incredibly dangerous. It's not at all like installing a power outlet. You can do that relatively easily and safely. These batteries will catch fire in the middle of the night, burning down apartments and they will kill many people.

So can store bought: https://www.youtube.com/watch?v=JCaDz_2YcGQ

So can galaxy notes, hoverboards, vapes, etc. So can poor electical installations, bridged fuses, cooking oil fires, etc.

These packs (18650 based) are a lot safer than "baggied" packs found in many fpv drones and RC cars, and those packs are factory assembled.

Firewise, i'm more afraid of an alcoholic with a cigarette, than of batteries.

What I find concerning is most people here would have seen expanded seams on a phone or laptop and known about the "puffy" battery within.

The rate of proliferation of gadgets with such batteries is crazy. So much of society already has so many of these little flashpoints in phones, tablets, toothbrushes, kids toys (electric scooter anyone?) - statistically your concerns are already valid without anyone being an electronics hobbyist.

So, compare the number of battery fires to eg. gas explosions, cigarette fires, oil fires due to cooking, etc.

Doing anything with mains power, water pipes and gas pipes is still done by many people themselves, and the risk is minimal.

Also most of the battery fires happened with factory installed batteries, be it in vapes, galaxy notes, or other devices.

Also: https://www.youtube.com/watch?v=JCaDz_2YcGQ

> same as with replacing an outlet at home, but more of a fire damage instead of a shock risk

Not a good comparison at all. The battery can burn down the entire building and kill everyone in it - or just burn them alive and leave them breathing. Don't forget all their property.

Your wall outlet will just knock you on your butt, afaik.

There's a fair bit of design, validation, and certification that goes into making sure a pack is safe. The spot welding and wrapping is just the final result.

Thermal design to make sure the pack doesnt overheat under normal conditions. There's the mechanical side to make sure that the pack can survive shock and vibe.

Getting packs certified to UN38.3 or IEC62133 are no small feats. Unsurprisingly, the certification process is not cheap. For 62133, we had to provide a ton of samples.

> You can also make them yourself at home, although it can get relatively dangerous if you don't know what you're doing... same as with replacing an outlet at home, but more of a fire damage instead of a shock risk, so definitely not for everyone, but with some basic precautions, can be done safely.

Did that for my semi-diy bike. Got an older Sparta with stupid DRM in it, removed all the sparta parts, made a custom PCB for the motor/hall sensors and had the NiMH battery replaced it with a custom 7s9p pack (in frame so was limited in options) resulting in a nice 650Wh battery instead of the 200Wh it used to have. Using recycled cells from a crashed scooter resulted in a (relatively) cheap, reused ebike.

From the pictures I get the sense this guy knows what he's doing. Sure his shop's a little dusty, and that fume extractor is maybe a little ghetto (better than my aquarium filter duct taped to a fan though).

It's hard to tell what those grey cells are being used in the pack, which is probably most important factor, but the construction of it appears solid. It's also evident from photo that he is disassembling a damaged pack. See the missing row of cells at the top, and corrosion on the bottom in this photo: https://149346090.v2.pressablecdn.com/wp-content/uploads/202...

They look like standard 1865 cells but obviously not high enough res to spot the manufacturer. I would imagine EVE though. CATL is too hard to get a hold of but EVE Grade A is still pretty easily available from Alibaba.

EVE would be my guess too, possibly INR18650-35V, which seems totally cromulent for an ebike.

EVE cells are also used in newer Ryobi power tools, it's worth pointing out: https://www.reddit.com/r/ryobi/comments/oxn53g/psa_ryobi_is_...

Simpsons did it.

I think you mean 18650? Unless 1865 is a new battery standard that has 10x the capacity, in which case EDC light with 1000 hours runtime here we go!

They are indeed called 1865 cells too. The 0 at the end, according to some sources, indicates the cylinder form factor; I couldn't find a definitive reference for this though.

But you will find articles and sources online referring to them as 1865 cells, like Wikipedia.

"An 18650 battery[1] or 1865 cell[2] is a cylindrical lithium-ion battery common in electronic devices"

https://en.m.wikipedia.org/wiki/18650_battery

I imagine Tesla calling their new battery a 4680 (opposed to a 46800) also leads to this usage.

Yeah it's abbreviated sometimes and I'm lazy. I should have added the 0 for clarity.

Various YouTubers do similar to build effectively Tesla powerwalls

It seems quite risky even for those that are careful. I recall one of the bigger channels ending up eating humble pie when they had a fire.

Not something I’d ever want to do unless I could house in in an outdoor shed quite far away from everything else

Question I have: is it just a bunch of cells wired up, or is there a BMS (battery management system) in there doing the things you need to do to make a battery safe and make it last: cell balancing is essential to make sure the pack will survive more then a few charges and rides before it will kill itself. Also I would not like a battery pack that does not switch itself off when voltages or currents get too high, which is a great way to start a thermal runaway. Not a safety issue, but important to make sure the battery is not abused is to prevent deep discharge voltage or charging the battery at too low temperature.

Hi -- editor of the piece here. There is a BMS, that's the main other component aside from the cells. We had that detail initially but it got cut for space.

A shame, because seeing how you can get and apply a BMS to a build is probably where much of the readership interest lies.

How 'programmable' is the BMS typically? is it arduino programming hard? Can you e.g. shape the charge profile. set the stop point, route around damaged cells? is the BMS field upgradable?

I'm guessing its a commodotized un-upgradable closed solution and you set the params on purchase (alibaba) and its how it works forever.

Take a look at the TI BQ79616-Q1, which has been used in some Tesla packs: https://www.ti.com/product/BQ79616-Q1

Yes, it's programmable. Even has eight GPIO pins. It would be "field programmable" in the sense that if you scraped the conformal coating off the pogo pin pads you could reflash it... which you probably don't want to do.

Despite what the article says, a BMS doesn't actually do many of the things you mention. It balances cells, monitors temps, and sets fault flags if something's wrong. A BMS chip does not charge the battery, it doesn't determine max voltage, (the charger does that) and it can't isolate a bad cell. (Because they're all welded together! Pack current doesn't actually pass through the BMS-- it only has thin balancing wires to each cell which can't handle much current.)

I take your point it doesn't do these things but the potential was there in hypothesis to control these things.

Sure, but the battery+BMS can't control those things. If you wanted to set charge parameters the easiest thing to do would be to buy a third party lithium ion battery charger, like the Tenergy TB-6AB, and set a capacity limit.

Usually the BMS in such packs does have control over the flow in and out of the battery: it can isolate the connections if there's an overcurrent or over/undervoltage (or overtemp). That's usually the main contribution to safety. And it's also pretty typical that the BMS is what defines the charging profile: the charger basically just follows instructions from the BMS (and if it doesn't, said isolation comes into play as protection). This doesn't necessarily all happen on one chip: in the larger packs this is likely distributed between a few different components, including a chunky contactor for the isolation.

Cheap active bms systems. Could be hazardous as well. But needed for charging from a 48v charger block.

I keep thinking Ripperdocs in Cyberpunk world. Looks dodgy alright, but it's in their best interest to not screw up because I know in Indonesia "homemade" usually literally means made at home, and houses in Indonesia typically share walls between adjoining houses, so if you burn your house your neighbors will not be happy.

Love to see something of a standard e-bike battery. Perhaps there is one in Southeast Asian markets....

Something roughly a liter, liter and a half in size. A standard, perhaps twist connector on the bottom. Various bike configs could incorporate a handful of these in locations that make sense for their bikes — the number of packs reflecting the range or torque requirements.

With a standard you could swap packs, get the cost benefits of scale...

You see this in Taiwan a lot already - https://cleantechnica.com/2023/01/11/gogoro-batteries-power-...

Standardized packs for low-end ebikes would be wonderful.

Those are for scooters though, not ebikes.

What's the difference and what is your point? They are 48v nominal lithium batteries.

Asia has standardise electric shooters while here, in the financial centre of Europe, we have dusty, noisy petrol guzzling bikes used for delivery. Have we fallen behind but we still think we are ahead? It's going to take another 10 years for any kind of standardisation to happen here

I wonder if we can get those in the U.S. It doesn't look like that's the point though. They seem to sell the infrastructure, the batteries are part of it.

https://jacquesmattheij.com/long-range-ebike/

Not the only ones!

I was super envious of this when he first posted it here...

However - I bought a ~7,000 e-bike and I love/hate it:

I have an Orbea Rise H30 - and its ~36 lbs. The problem is that the magnets in the motor are always engaged - meaning that even when the bike is 'off' I am fighting against the magnets - and it governs me and when off, no matter how hard I pedal - I cant get about 11 miles an hour.

It is a type 2 - so it is not supposed to boost you passed 20 miles an hour - but instead it effectively governs you to 20 mph. Its very hard to get it much faster - the fastest I have gotten to is 24.5 mph. Downhill.

However - when the battery is powered - its great, except you have to only keep it on BOOST which is the highest of three settings (eco, trail, boost)

I'd not buy this bike again. It range is really around ~30 miles - and they have a range booster battery pack for $600 - and I should have bought that when I had the money to throw at it... but yeah the bike sucks when the battery dies.

On my bike, I found that disconnecting the battery made the magnets spin freely.

I have a Shimano middrive bike that weighs 50lbs that I purchased on closeout for $1500. It rides like a nice, albeit heavy, bike with the motor turned off.

You can do better then that.

CYC motor kits can take up to 72v, and they don't care about talking to the BMS of the battery, so you can pretty much run any battery.

The final reduction is external, so they sell different chainring sizes. With higher voltage, you get more motor speed, so you can do a bigger reduction for the same power, which means lower motor required torque for the same wheel torque, which gives you efficiency.

I have the 52v setup from them on a full suspension mountain bike, with the 416wh battery, and I have done 30 miles on it with pedal assist and knobby mountain bike tires and basically got the battery down about halfway (im fairly fit and have a higher FTP so I don't require much assist).

If I was to build a setup like in your post, with a big 72v battery taking up the entire front triangle of the bike, and use faster rolling tires, I could either have an ebike that can probably keep up with cars on a highway under throttle, or in the pedal assist mode, do over 100 miles.

More of this please!

It's astonishing how anti-modular various industries are. Even batteries, which for all their "oh no gonna blow" are really quite simple components. But why are cars not modular? How about HVAC? Housing is pretty modular.

These home made ebike batteries regularly catch fire and burn down apartments. Quite a lot of apartments in Australia are banning taking ebikes inside now.

Regularly? That means that some nontrivial fraction are guaranteed to burn. I think you mean that it happens at low probability but is eagerly covered by media.

In any case, the fault is almost certainly either physical abuse (which has nothing to do with accessibility/modularity) or simply bad chargers (which better access would actually mitigate).

Packs, battery packs.

This is very common for DIY ebikes.

It used to be that one assembled batteries of cells. But language changes I suppose.

In this case, each cell is also a standalone battery (an 1850 I presume). Assemblage of these is either called a module or a pack.

An 18650 is a single cell. (Or a battery in modern parlance.) Now, get off my lawn! :-D Just kidding! The terminology shifted. But a cell used to be the single unit of chemistry and catode and anode that gives the native voltage. So an 18650 would be a cell. A 1.5V alkaline would be a cell. A 9V alkaline would be a battery of six cells! And so on.

I'm not saying it's wrong nowadays to say an 18650 is a battery.

Not even disagreeing with you, but it's a funny evolution of language when you consider the origin of the term battery.

https://en.wikipedia.org/wiki/Artillery_battery

We owe the term to Benjamin Franklin, who used it to describe what you're referring to as a pack (although Leyden jars are considered capacitors rather than batteries in modern terms).

https://en.wikipedia.org/wiki/Electric_battery#Invention

Relevant: "Louis' front door goes BOOM courtesy of UnitPackPower battery" https://www.youtube.com/watch?v=JCaDz_2YcGQ

Lithium Ion (and especially LiPo) are not to be trifled with, small things might matter (such as whether the battery is under mechanical stress, dented or bent). I would never want a large battery from a non-reputable supplier around my home.

There's a small youtube channel[1] I follow where a guy I think is from Indonesia builds his own handheld coil guns and railguns including his own charging circuit designs. Pretty crazy/fun stuff. There seems to be quite a bit of an electronics hacking scene going on there.

[1] https://www.youtube.com/@DNAP460/videos

Wow this is scary. LiPo are very dangerous and even NMC which are stabler are very error prone when assembled in an ebike pack: the cells need to be high quality (LG, Panasonic), the assembly need to be very careful (so many ways for the interconnects to become a liability and cause a fire) the BMS needs to be quality (or it'll overheat and cause a fire). It's hard to make it right when careful, and even decently sized companies mess it up.

Slapping together some LiPo? It's just a matter of when, not if.

Recently published very relevant talk by Grin: https://youtu.be/j92Gt4VviSQ?si=0TV_HqZBEBuVDqdx

Otherwise I think these things are super cool, but in the case of lithium ebike batteries, they look so innocent and easy to build, and are so dangerous. I'm speaking from being humbled myself after building two NMC packs with cell-fuses, a spot welder, being careful... I'm dead scared of my packs.

Wow this is scary.

Not really.

LiPo are very dangerous and even NMC which are stabler

LiPo refers to lithium polymer, which doesn't mean a different chemistry. It means "polymer electrolyte instead of a liquid electrolyte".

https://en.wikipedia.org/wiki/Lithium_polymer_battery

are very error prone when assembled in an ebike pack

There are billions of 18650 battery packs out there now in general.

the cells need to be high quality (LG, Panasonic)

No, the cells need have their specs correct and the packs need to be built according to cells' specs.

the BMS needs to be quality (or it'll overheat and cause a fire).

The BMS is there to limit things like discharge voltage, charge voltage, discharge amps, etc. It makes things safer.

You may think so, and I encourage you to watch the video I shared. I held many of the same conclusions/approximations until learning of Grin's experience.

The video you linked is problems that can happen and things that can go wrong. It seems more like something the battery makers should watch instead of proof that batteries are inherently unsafe.

The article is about battery makers.

Who do you think I was talking about when I said "It seems more like something the battery makers should watch" ?

My understanding of our conversation:

* You: That video is not relevant because it's about battery makers

* Me: The conversation is about battery makers

It seems I'm missing something.

The person who linked it was saying it is evidence of batteries being unsafe because it goes over things that can go wrong.

I was saying it's educational for battery makers and the video isn't about batteries being unsafe, the guy in the video makes his own batteries and is talking about what to avoid.

They aren't slapping LiPos together. They aren't even using LiPos. LiPo are usually single small cells pouches in phones and gizmos. These are Li-Ion 18650 cells like Samsung 50e's being nickle spot welded into ~60V arrangements, with every 4.2V "p-pack" getting a wire to the Battery Management System circuit board. All charge and discharge does thru the approval of the BMS and gets cut off if any cell shows anything abnormal (short, too much resistance (voltage dipping), undervolted, overvolted). The photos look just as professionally made as another other factory. Unwrap literally any random e-bike's battery and you'll find identical construction. A few rare brands also pot the battery in thermal epoxy to make them even more safe. Yes fire and liability are scary for battery pack builders but this guys shop doesn't appear to be doing anything bad.

Why not use LiFePO4? Those should be much more stable.

Power density is much lower. On a vehicle you have to pedal one the power is out, weight savings matters.

Having to pedal without power from battery is extremely rare on e-bikes. They have range of 100km+ and few people bike that much between charges.

LFP:s are less popular for DYI because you need a much smarter BMS to deal with the flat voltage curve when charging. A cheap, easily available open source LFP BMS should solve that.

You don’t need a “much smarter” BMS for LFP, Daly BMS for LiPo and LFP are roughly the same price.

For SoC many ebike BMS just use voltage curve to give a rough approximation. But with LFP you need a shunt and a coulomb counter, because the voltage curve is essentially flat until the very last Wh.

I ended up pedaling without power on a 3 hour trip in the mountains on a 750Wh battery/85Nm motor. Can be easily done ;-)

I am building similar battery packs for long range uavs. We have many different configurations. Like 12s24p. 48v with total of 252 4.2v cells. We put them in 3d printed holders and spotweld them. Takes about 30 minutes to make one battery. Bms systems are available widely. Its rare to have dangerous issues. Even with chinese clones. Most of the accidents happening when nickel strips are cut and accidentally falling on open battery packs.

I agree that it's fun and can often be safe if built correctly for the right application. But I think UAVs don't experience the same beating and vibrations that ebike batteries do, which I think is what the bigger problem is with ebike batteries in particular. Unless carefully built, things like balance wires can shafe and cause a short, the spot-welded tabs can break off or the connection resistance increase, leading to hot spot. The BMS can have hot spots (FET based ones in particular) that lead to failure or electrical fires over time. Humidity mixed with various electrical potentials on nearby PCB traces causes corrosion and eventually failure of the BMS, etc. And it's not all the BMSes that are built the same, they may all have the same set of features on the happy path, but they're not all created equal when their PCB starts failing and fail-safes are required.

Basically in a "tough" environment like ebikes, I think the aging of the pack is much accelerated, which leads to lower mean-time between incidents. Combine that with the profile of the average buyer (wants the cheapest, longest range battery they can get) and it's an even higher probability.

Don't get me wrong, I absolutely love custom DIY packs. It's just way more dangerous than meets the eye, especially in dirty and high vibration environments.

It’s not just fire but explosion as well with bad battery packs. Some years ago some friend bought a “comparable” laptop battery off eBay for an older laptop. They were charging it one day and battery exploded. Fortunately they were not sitting in front of it. I was in the office when my friend got the call from his wife and asked me to come look at the computer. We arrived with smoke in the room and little fires burning in different corners of the room with a scorch mark on the desk and the laptop in the middle of the floor with smoke wafting out of it. I dug some charred plastic out of the battery compartment and hooked it up to external power and it booted ok. Be safe out there kids.

The article goes to great pains to emphasize how concerning this is and how much of a safety risk it is seemingly without finding a single actual incident where the independent battery builders' batteries caused a problem. Frankly, given the level of quality control I've seen from large brands lately, I'm skeptical that the guy who's made it his business to build batteries for the last 20 years is delivering a worse product than what I'd get buying retail.

This is just a hit piece from someone in the battery industry.

The dead giveaway the author has been in the battery industry for a long time is this: > Packers often use 18650 lithium-ion cells — essentially a larger, rechargeable version of a standard flashlight battery.

Then calling a group of people "packers" shows the author wants to label and dehumanize then.

I cant wait for outfits like this to pop up in the states. I have a couple of battery packs that are dead and I do not have the time or patience to rebuild. They are gonna go to CL free, but I looked for local services that can rebuild them.

As more battery packs begin to fail this will become the norm.

They do exist.

Off the top of my head Tenergy is one that operates in the states, but there's tons of them out there.

I can imagine indonesia's low wages supporting manual labor to rebuild these battery packs, but in the US or Europe surely the cost of such labor precludes such labor, or otherwise requires more automated methods?

Comments in this thread are hilarious. Making battery packs by connecting cells together is neither difficult nor especially dangerous. It’s soldering. Sometimes you’re just connecting wires to terminals. Anyone can do this. It’s not a big deal.

In other headlines: “Tech worker builds batteries in his own room after work”

This is just assembling cells, not building a battery from scratch.

those in the diy space are very well aware about assembling your own batteries as mentioned by others.

their approach does not seem too different from the norm, but it is interesting to see it happen at commercial level. from an economic standpoint, the countries producing commodity cells can stand to benefit a lot from cottage industries like this to increase electric mobility.

I don't know Indonesian import law but I would guess that this guy making batteries for his local business might have better quality than what I assume is the alternative, imported Chinese batteries. I wonder why so much concern over safety. I would be much more concerned about Chinese imported batteries since you don't always have a brand name and QC.

> since you don't always have a brand name and QC

Some guy DIY-ing batteries in his shop is pretty much the epitome of "no brand name and QC" though. Seriously, look at some of the pictures in the article. Those botched together mains wires alone look like a fire risk.

Quite apart from the circumstances of their creation, the homemade battery packs themselves can also be quite unsafe as some/most shops use any secondhand cells they can get their hands without regards for discharge ratings etc. That sort of imbalance can easily lead to fires during use, which is obviously not great when the driver is in busy traffic at the time.

> Those botched together mains wires alone look like a fire risk.

There is nothing inherently unsafe with bolting power strip onto the wall.

> Quite apart from the circumstances of their creation, the homemade battery packs themselves can also be quite unsafe as some/most shops use any secondhand cells they can get their hands without regards for discharge ratings etc. That sort of imbalance can easily lead to fires during use, which is obviously not great when the driver is in busy traffic at the time.

Not reading the article before yapping your mouth eh ?

> Ady Siswanto, owner of e-bike workshop Dyvolt in Jakarta, told Rest of World he takes care to match the internal resistance and capacity of the cells.

Most of the "serial DIYes" know that just fine, as it is blindingly obvious in performance of batteries and if you're making it a business you'd not have many returning customers... except ones returning for a return.

And let's not pretend name-brand packs don't have "accidents"

He works under his own brand though, I would argue that batteries made by the guy down the street have a higher brand awareness than "COCO" batteries which might also sell under name "BOBO", "AOAO", "AKKO", "LMYW", etc.

I am only pointing out that I would be concerned regardless of the source, chinese or local but suspect the local guy has a greater incentive to maintain his brand than the imported brand from china.

> Seriously, look at some of the pictures in the article. Those botched together mains wires alone look like a fire risk.

I'm guessing you haven't been to Indonesia. This style of wiring is common in businesses and homes in Indonesia, Thailand and lot of poorer asian countries. The regulations are weak or unenforced. Often unlicensed people build houses, run power, water etc.

It's (probably unintentionally) dishonest to judge this by a first world standard.

Physics is the standard - it ignites or not - and it doesn't care where you are.

> better quality than what I assume is the alternative, imported Chinese batteries.

You do realise that China makes some of the worlds best batteries right?

There is a reason why BYD, EVE and CATL are in the news all the time and it's not because they suck.

Quality wise Chinese/Korean/Japanese batteries are all pretty much the same on NCA/NCM chemistries. China has a big advantage in LFP but LFP is shitty for an e-bike because the reduced density penalty is much more meaningful than in a car.

Those companies make cells of course but there is also plenty of high quality BMS available and fully assembled batteries out of China too obviously.

China also makes some of the worlds worst batteries. (Source: all the products I had to return after 1 or fewer successful charges.)

They are doing exactly what the advocates of free market dream of. You want to pay as little as possible, you get the crappiest stuff, you are willing to pay more to get top quality, you get good stuff.

In many product categories there is no top stuff, just keep buying the crap stuff until you find the specimen that works. Maybe "keep repeating" is a proxy for free market goodness, I can honestly not tell anymore. :-D

That would be fine if there was a way to differentiate crap from not crap. Price is a signal, but an increasingly shitty one in that I can pay a high price and still receive crap.

The free market is happy to sell me crap at high prices with no ability to know that until the deal is irreversible.

The theoretical free market also has perfect information, and the current markets actively work to obscure that.

They are having huge issues with e-bike fires in China. Here you have an article with two Chinese researchers weighing in on the issue.[0] According to them low quality batteries are the reason for the number of deadly fires.

So yes, Chinese ebike batteries are on a whole of low quality.

[0] https://www.sixthtone.com/news/1013638

Given the numbers cited there it looks like Chinese e-bikes have a fire rate of 0.002391% per year. From a quick search it seems like there were about 130 e-bike fires in NYC in 2022 out of a population of about 65000 e-bikes, so NYC based e-bikes have a failure rate of 0.2% per year which seems significantly worse than the cheap ones used throughout China.

Did you read what the experts said? It doesn't matter if the incident rate is higher in NYC, anything about NYC has no bearing on this. The fires in china are due to low quality batteries.

I don't think there has been any sort of reliable survey on the quantity of ebikes in NYC, and 65,000 is likely to be extremely low. There is no registration or point-of-sale reporting requirement.

There are also large quantities of unregistered electric and gasoline mopeds and motorcycles, many of which are also labeled as ebikes by either their manufacturers/importers or public authorities when involved in an incident.

One can purchase custom-made ebike batteries in NYC from shops similar to the one in this article, often with substantially worse finishing/packaging quality and unknown BMS quality. And said batteries are often run hard in delivery service in 4-season conditions, including exposure to temperatures well below freezing and salty slush spray, then charged via chargers and cords of unknown quality plugged into what are often pre-WWII electrical systems.

The FDNY is appropriately raiding custom battery shops in NYC, since there doesn't seem to be an appropriate regulatory system yet for custom-manufacturing this sort of energy storage device in a dense urban environment yet: https://ny1.com/nyc/all-boroughs/news/2024/02/09/queens-biz-...

Do you really think these bicycle batteries are being powered by BYD? Like I said I don't know the their market well but if its similar to other markets in the region, they are importing low quality generic branded stuff that may be worse off than those local manufacturer who have a real incentive to try to product higher quality products.

Do you really think there are tons of dodgy Chinese companies producing battery cells? A notoriously technically difficult, capital intensive and above all massively competitive business with tiny margins unless you are running the absolute best process at enormous scale?

No. There is just a handful of companies producing cells at reasonable scale and cost. Pretty much every cell you can buy from Alibaba (which is almost certainly where these e-bike pack makers are buying from) come from just 7 companies: CATL, BYD, EVE, CALB, Gotion, Sunwoda and Farasis.

All of these companies make high quality cells and these are definitely the only ones with a good enough price/performance to shove in a hand-made e-bike pack and make a profit.

This notion that Chinese batteries are somehow bad is ludicrous and the lengths people go to state as fact something they clearly have no experience with is intellectual dishonesty at best.

I can see you are very passionate on this topic. I did not realize in the article that these shops were actually making individual cells but the rather the complete pack. My notion was that the complete pack may be safer than complete packs coming from china under generic fake names. Thanks for clearing it up. You clearly have a lot of experience in this area with incredible honesty but low capability at following thoughts.

The fact is that there are demonstrably under-specced batteries being sold. (https://www.youtube.com/watch?v=qMZuHMlRw_0&t=579s)

Is this just a case of people buying reputable batteries and selling them under their own brand name with higher specs? If so, why do these 7 manufacturers make bad batteries?

Clearly there are plenty of badly made cells out there, so I think I'm misunderstanding something.

> Do you really think there are tons of dodgy Chinese companies producing battery cells?

Are you serious? Yes, obviously. Spend 5 minutes on Alibaba looking at the panoply of companies selling cheap cells, and reading forum posts from people who build their own batteries unfortunate enough to buy those cells.

The quality of individual cells does not necessarily have any bearing on the safety of the finished battery/BMS/charger.

Never suggested otherwise.

Are those LiPo or LiIon? The articles mention both, and the image looks like LiIon

Photos are showing Li-ion 18650 cells afaict

Those are the most common for e-bike batteries

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