Wrong charger used

[Wurly]

I was away this weekend and my wife needed to charge her 36V 10Ah lifpo4 ping battery. (I reckon' it was no more than 50% depleted but i have no way of telling). Unfortunately she picked up my charger (5A)i use for a 48V 15Ah Ping lifepo4and uplugged it in. Checked it 2hours 30mins later, all leds are illuminated (no surprise) and she reports that the green led on the charger turned off.
So figured the BMS did it's job and shut off the current to the battery to prevent it over charging.....or did it?
The charger is CV/CC When the green led on the charger turns off i presume the current flowing into the BMS stops? so what does the floating voltage actually do? in this case i think the cells might have reached 4.88V!!! i am really surprised she didn't set the whole thing on fire. she used the bike today no problems. I only found out tonight. Not blaming her of course, it was my fault for not having the chargers marked in a way she could understand. Has lasting damage been done to the cells?

 

[dnmun]

if your 36V ping pack has a BMS then it should not have been able to overcharge the cells no matter what voltage you used to charge.

did you actually measure cell voltages?

the lifepo4 will never catch on fire even if you overcharge it at high current above 5V.

 

[Wurly]

Do you mean cell voltages after the battery was charger with the wrong charger? no as it happened 1 1/2 days ago.
I have not measured anything yet. The battery in housed in a tin box and will take some effort to remove.
Reassuring to hear it may be ok

 

[dnmun]

what was the pack voltage when you removed it from the charger?

there is no way to know for sure unless you take the battery apart and can test the charging mosfet to see if it has shorted but you said the green light came on the charger so the BMS must have been able to turn off the charging current when it hit the HVC.

depending on how long it was on the 48V charger the cells may have charged up above 3.7-3.8V which is not really damaging if that way for a short time.

 

[Wurly]

This is the problem, i wasn't there at the time to prevent her using the wrong charger let alone measuring pack volts when she did it.
Wimmen....don't you just love 'em :wink: She said does it matter?

She's needs to use it tomorrow, so i think i'll charge it with the correct charger when she gets home and see if the pack looks like it's balancing ok. If not i'll dismantle it and check cells volts

 

[dnmun]

if the green light was on the 48V charger, then the BMS was shutting it off and preventing overcharging. so she is right in saying it should not make a difference.

 

[Wurly]

I'll tell her that, it'll make her laugh...
thanks for your help

 

[wesnewell]

http://www.youtube.com/watch?v=wkJM8MZkFKU

 

[dogman dan]

I think it should be fine. But you might consider changing to a different charge plug on one of the packs.

 

[jay7264]

that headway flaming up was put under extreme stress a normal charger couldnt produce those results cause it doesnt have the amps to create that kind of heat