Want to learn to restore batteries. Where to start?

[Chris Maluszynski]

Could someone point me to any useful resources for learning how to restore batteries - disassemble, diagnose, repair, swap cells etc.

I’ll mostly be working with 18650 cells.

Thanks!

 

[soundwave]

you dont swap cells with new ones its all or nothing its ok for low voltage and amps for flash lights but ebike batts forget it.

just say you have a 59 cell pack but one cell in every bank is hammered so voltage will drop and cut off even tho the new cells have plenty left.

 

[Nealh]

The best resource is probably the mine field that is Endles sphere , lots of battery threads/ guides on there .
Swapping cells out generally isn't a good idea on and older battery.

 

[Chris Maluszynski]

So the companies reconditioning packs are actually replacing all the cells?

 

[flecc]

So the companies reconditioning packs are actually replacing all the cells?

Yes, always if they are reputable companies. That is why there is often not much, if any, saving.
.

 

[thelarkbox]

An interesting vid on youtube from linus tech tips recently where they attempted recelling a couple of significantly smaller 18650 packs 8x and 4x iirc..

It indicates that learning to weld batteries could be both hazardous and expensive - tho the welder used seemed to be a bit overpowered based on how often they filmed he electrodes welded to the battery/strip post arc... (not that i know anything about battery strip welding at all..)

 

[Nealh]

So the companies reconditioning packs are actually replacing all the cells?

How can they provide a guarnatee if older cells are used , they will under perform the new cells .

 

[AntonyC]

There's a strong lobby pushing for regulation that would mean reconditioned batteries couldn't be sold, and perhaps not used, so you'd have difficulty charging for this service.

Also a bike battery fire is often very quick to develop and intense. For working with batteries ideally you need safety knowledge 'in your bones' from years spent on similar work, so that old habits look after you in any momentary lapses, as happen to all of us. So I'm afraid in short I'd say 'Don't start from here'

 

[matthewslack]

It is not entirely clear, but it sounds to me like you may be planning to fix broken batteries as a business.

My advice is don't. The consequences of one failure are far too high for it to be worthwhile, and there is no way you can mitigate the risks sufficiently.

Generic batteries are so cheap now there is no point messing with those, and Bosch etc are engineered to make the task almost impossible anyway.

Just remember the flat fire a few months ago with fatal outcome caused by an ebike battery. Don't risk being responsible for the next one.

 

[sjpt]

With a reconditioned battery you are paying UK labour charges for an individual item. With a new battery you are paying China or similar labour charges for a mass produced item. A reconditioned battery is only worth it if the original is some proprietary battery that can't be replaced, or is really excessively expensive to replace.

 

[StuartsProjects]

So the companies reconditioning packs are actually replacing all the cells?

The safer way to make eBike Batteries is to use cells from the same batch, so all the cells are well matched.

If one cell fails, then it is possible other cells are close to failure too.

If this is a business, then carefully research how much liability insurance for such a business will cost you.

 

[StuartsProjects]

There's a strong lobby pushing for regulation that would mean reconditioned batteries couldn't be sold, and perhaps not used, so you'd have difficulty charging for this service.

And even if they don't go as far as banning reconditioned batteries, it would be no surprise if a strict certification process of companies doing re-furb was enforced.

 

[saneagle]

Say you had a folding bike with some sort of unique in-frame battery, the cells wore out or some became defective, so you decided to re-cell it. How would anybody know? If you did it badly and the battery caught fire, any evidence would be destroyed.

For Chris: Repairing batteries is not really an economic proposition. For all the standard types, you can buy a new one cheaper than the parts to re-cell it. Many of the others have comms and are locked to the bike. I'm guessing that the new regulations will either encourage that a lot more or make it mandatory. That only leaves a few obscure batteries on bikes that came and went. If you have such a battery on your bike, it's probably worth doing, but you need to think about the cost of the welder and the cell chargers/cycles. The cheap Amazon chargers don't work very well. You need a Sunto type with a transformer in it or better.

Rather than ask us cryptic questions, it would be better to say what you're thinking about doing, then we can advise properly.

 

[Chris Maluszynski]

Hey. Sorry for being vague. I have no intention of making this a business, I only wanted to revive some old batteries that I have laying around that are not taking charge. It sounds though that this not advisable? I am sure some of the cells in these batteries are still good. Maybe those could be made into a smaller capacity battery if no cells are to be replaced?

 

[Chris Maluszynski]

Or if NO cells are to be reused, wouldn't it still make sense to use the case and BMS and building a pack from new cells that would fit in the old case? or is this also just a waste of time/money , and better to mount a cheap generic battery on the frame/in a saddle bag or bike rack?

 

[Nealh]

If the case is aspecific type or one that one can't find to replace then yes one can simply recell the case. As to whether the BMS is worth reusing is dependant on the cause of any cell failure. If they drained then the BMS might be at fault.

 

[saneagle]

Or if NO cells are to be reused, wouldn't it still make sense to use the case and BMS and building a pack from new cells that would fit in the old case? or is this also just a waste of time/money , and better to mount a cheap generic battery on the frame/in a saddle bag or bike rack?

The only time it makes sense to re-cell a battery is if it's something special that couldn't be replaced by any available battery. Regarding the used cells, you can disassemble them into individual cells, test them and use them in powerbanks.

Pardon our interruption...

Cheaper version, but a bit more complicated:

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Powerbank cases:

Pardon our interruption...

 

[StuartsProjects]

I am sure some of the cells in these batteries are still good.

Why are you 'sure' ?