Battery died

[aardvark5]

I have two identical batteries because I swop out with the two bikes I have.
Last night one of them died, completely dead, zero led lights on them, turned off & one, nothing.
Because of disability I had to ring the wife to bring my spare battery and that got me home.

I'm a little bit handy with screwdrivers and a meter is there anything I can try?

Thanks

 

[saneagle]

Yes, open up the case so that you can see the cell-pack and the management pcb (BMS).

Find the positions on the BMS where the red and black power wires from the cell-pack are soldered and measure the voltage there, then unplug the multipin connector and measure the voltage of each pin on it with your black probe on ground where the black wire from the cell-pack is soldered. The pins represent the cumulative cell voltages. Subtract each from the next to get the cell voltages.

If the cell-pack voltage is over 31v and each of the ten cells are over 3.0v, the cell-pack is OK.

Another good clue to problems is to fully charge the battery and measure the voltage . Anything below 41.0v indicates that it needs some attention. If it doesn't charge, you have to open it and check the charge fuse first.

 

[aardvark5]

Thanks and apologies but I was worrying

 

[Nealh]

Snapped of balance/sense wire , one can spot weld it back on or if no spot welder carefully solder it back on . Try and avoid heat direcly in the center of the negative cell end, instead place the end to be soldered ( if soldering ) to the side and off center, it matters not if you place it slightly to the lhs or rhs.
Tin some solder on the cell end and the connector end then simply add heat when they are together .
Once the sense wire is connected again charging should occur , BMS originally shut down /switched off because it sensed a fault.
Before charging though I would check the 10 cell groups first for voltage balance to see if there is a wide discrepency.

 

[aardvark5]

I'd already soldered it back before you wrote that
It seems to be OK.

 

[Nealh]

Good to hear , BMS designed to do the job it is meant for when it senses an issue.