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Comment by jdietrich | Hacker News Reader

>What special tools, skills, and experience is required to unscrew a battery pack?

An e-bike fire is no joke. If you don't know what you're doing, you can easily turn a li-ion pack into an incendiary device. Aside from the safety issues, there's a huge reputational issue for the industry. I don't like the idea of restricting the right to repair, but I really don't like the idea of sharing an apartment building with some guy who replaced the cells in his e-bike battery pack because he watched a YouTube video and figured that it can't be that difficult.

https://www.youtube.com/watch?v=v5jGYWhGnJ4

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I think you may have missed my point, but that’s my fault because I was being facetious.

When I need to replace the battery in my car, I don’t open up the battery to replace the plates and acid. I buy a new battery (from a brand and store of my choosing) and recycle the old one.

Why are ebikes different? Why are people having to replace the cells in the pack? Because the manufacturer has made it impossible to get a aftermarket replacement battery pack.

So I’m saying the solution is for manufacturers to build their products in a way that makes it easy and safe to replace the battery (without lockin), instead of intentionally building products that are difficult/unsafe to repair and using that to claim the product needs to be excluded from right to repair.

So then, e-bike replacement battery packs should be as easily available and as easily changeable as car batteries. Problem solved ? What am I missing ?

> What am I missing ?

That vendor lockin and difficult-to-replace parts were a significant driving force behind right to repair, yet ebike manufacturers have successfully used artificial difficulty as a reason to exclude their products from the law.

I'm looking at a 2nd hand ebike for sale and the battery on it talks to the computer on the handlebars and reports its charge level. It's not like a car battery which is presently just a battery.

It’s been shown that we can write standards for these things. In fact you would build on an existing baseline like i2c. they almost certainly already do already

The CDC (charge-discharge controller) of many BMS (battery management system) devices can already communicate the charge state. My home built e-bike uses a one-wire protocol, newer ones use a serial protocol. Even the plugs have become standardized these days. There are so many manufacturers selling components and kits, and 99.9% of them interoperate with components and kits from other manufacturers. Pick the bike computer you like, the form factor of the battery pack, size of battery pack (they all use 18650 cells anyway), BMS, CDC, wiring harness, motor. It is no more complicated today, and actually far easier so long as you size the motor to the bike frame and the battery to the motor, than assembling a desktop computer.

I've gotten really into commuter biking, and I have a nice frame sitting there. I can solder, build power and BLDC motor controllers, and do light machining. but somehow the idea of learning wheel building is just too involved for me :-)

do you have some references? I would love a little hub motor for the hills.

You don't need to do any wheel building yourself. You can buy the hub motor pre-installed in a wheel. Simply purchase the proper diameter wheel for your frame. The only aspect to keep in mind is to get the right sized motor for your frame. Too many people chase the "big number" hub motor wheel, picking up a 3KW or 5KW motor, and installing it on a frame that will shake itself apart, or a frame that isn't made to travel at 40MPH/60KMH with brakes incapable of handling that speed. If you do end up purchasing just a hub motor, and want to fit it to your current wheel, find a good bike shop that does wheel rebuilds, and have them put the motor in for you and tension the spokes. Takes like an hour of their time. My old motor is 500watt, which gets me a top speed of around 18MPH/30KPH on the flat and a 15 mile range. I am contemplating going to a 1KW motor. Eventually. Maybe.

It's probably using SMBus -- a standard protocol for exchanging information like state of charge: https://en.wikipedia.org/wiki/System_Management_Bus

If it's not, then I agree that the proprietary shit has to go.

Ah - thanks. I'm new to ebikes.

It’s most often a custom protocol, every now and again it’s CANBUS.

Quite often it also needs an activation code or the BMS will kill output on a draw >5-10A after a few seconds

It is still just a battery. The battery on that ebike like every other ebike on the market is actually exactly the same: an array of common 18650 batteries packaged into a plastic “pack”.

Many cars require that the battery is coded to the car. The reason (excuse) is auto-stop/start.

BMW have been doing this for over 20 years.

Then your apartment complex should ban ebikes repairs, not the state.

Sometimes a regulation needs to be done at the government level for the protection of everyone. For instance, we didn’t leave it up to individual apartment complexes on whether or not they wanted to implement ADA requirements or fire detectors.

It’s generally bad policy to leave it up to landlords on whether or not something should done or banned for safety reasons. Their default mode is to do nothing.

Try https://batteryuniversity.com/

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