Hi all.

I recently inherited an old cargo bike from a neighbor. It’s been standing outside for a good while. The battery seems swollen. I guess I should not even attempt to charge it?

It has many more connectors than I’ve seen before. If I wanted to try the bike with another battery how should I connect it? It has a bafang mid drive.

Don't bother with that battery. It's only the outer two pins that do anything. Check on the receiver side which of the corresponding pins is the positive, then run any 36v source to those two pins on the receiver. You can use any 36v charger as a source or any 36v battery you have lying around (charger is easier). Test it with the wheel off the ground and be gentle with the throttle to keep the load low enough for the charger.

Just in case Visible swelling through the hard plastic exterior case is a VERY RED FLAG

 

And since your asking here you have the good sense to check

so just to be 100% clear..

IMHO DO NOT ATTEMPT TO CHARGE THE BATTERY IT COULD END VERY BAD

Dont leave the battery near to or on anything flamable, like wooden decking, or a house.

 

You dont live anywhere near Wales do you ?

Dont leave the battery near to or on anything flamable, like wooden decking, or a house.

 

You dont live anywhere near Wales do you ?

 

Why, do you want to burn Wales down (JR Pontrefendegaid)

Dont leave the battery near to or on anything flamable, like wooden decking, or a house.

 

You dont live anywhere near Wales do you ?

 

I'll be careful with it, but really, could it just spontaneously catch fire?

I'm in Norway, so safe distance from Wales! (Why?)

And what are all those connectors for?

I'll be careful with it, but really, could it just spontaneously catch fire?

I'm in Norway, so safe distance from Wales! (Why?)

 

"Even if your device still works, if the battery is swollen, the battery must be replaced immediately, using the device or leaving it connected to power can be dangerous."

https://www.reading.ac.uk/health-safety-services/fire-safety/lithium-battery-information/i-have-a-swollen-lithium-ion-battery-what-should-i-do

 

Edited June 26, 20241 yr by lenny

I doubt it will spontaneously combust, the energy in most of the cells probably dissipated in the expansion But if you start pumping fresh amps into it it could behave unexpectedly..

 

As for the number of connections, its probably a future-proofing of the battery format if for example 1 connector pair can handle a 20amp draw 2 x pairs could handle upto 40a and 3x 60a ?? (just guessing)

I'll be careful with it, but really, could it just spontaneously catch fire?

I'm in Norway, so safe distance from Wales! (Why?)

No. It won't catch fire. They're all hysterical. I've had and still have many swollen batteries like that. They're probably as inert as a battery can be. It probably hasn't got any charge in it, but treat it with respect and don't do anything stupid with it.

I'm in Norway, so safe distance from Wales! (Why?)

 

Just checking if I was safe.

 

If its been swollen for while then yes, its unlikley to burst into flames now.

 

Its unlikly that most people would win the lottery, yet a lot of people do play.

I'll be careful with it, but really, could it just spontaneously catch fire?

 

If you're not going to safely dispose of the battery, perhaps monitor it's temperature and remove it from your home when the siren sounds?

 

https://www.pedelecs.co.uk/forum/threads/home-ruination-by-ebike-battery-fire-expulserating-preterminator%E2%84%A2%C2%AE%C2%A9%E2%84%A0.46934/

 

This is a badly edited promotional video with an awful soundtrack, which I'll get around to improving at some point, but it illustrates the point up to a point:

 

 

And what are all those connectors for?

 

Extra connections (unused) could be for a manner of reasons but in most cases aren't used.

The two outside pairs are for discharging /connection of a generic two wire battery.

The next pair of inner are sometimes utilised for on bike charging where the main battery charge point is inaccessible , instead the battery carrier/holder will have a separate charge port that becomes live once the battery is in situ ( I have one such battery/carrier like that) and the battery charges thru those pins. The pins are wired seprately to the BMS charge and not in parallel with the outer pair.

 

Other bike construcctors may choose to use a proprietary battery set up a bit like Suntour, Gtec etc,etc there the extra pin outs may be to register that one of their batteries are being used thus preventing other batteries being used so extra thin wires maybe connected as in CANbus systems.

 

In most cases though only one pair are generically used.