Is my LiPo toast?

[fatbbq]

So I accidently left my serial harness on my 3 pack of LiPo's when I plugged the balance leads into my parallel charging board.
First balance lead was fine. The moment I touched the second balance lead on the board, a HUGE spark. The positive pin on the JST-XH connector is all black now.

So I thought losing a balance lead on a LiPo is no big deal, just charge it with no balancing right!?

But my charger is saying it's a 3s when it's suppose to be a 4s pack, even with no balance lead in the smart charger. Did I destroy a cell? Is this pack now Junk?

 

[dogman dan]

You'll have to peel the top of the battery wrapper, and see what melted. Often that type of short will toast the tab on the first cell in the line.

You do have a 3s pack now, or will, when you move the (usually) red wire. But right now, its disconnected, and a 0 s pack.

Likely you did in the parallel board too.

 

[Punx0r]

You shorted the pack via the balance leads. Considering these are teeny, tiny wires, they shouldn't be able to carry enough current to blow the tab off a cell unless there is something wrong with the tabs and/or connections.

Better take a look like Dogman says.

 

[skeetab5780]

Is your lipo toast? The answer is no im sure they are fine.

But im sure the balance leads on both things you blew up are toasted in some way.

 

[amberwolf]

If it was plugged into the charger when the incident occured, it could also have damaged the charger.

Does the charger read correctly on other packs?

 

[fatbbq]

The charger is fine.

Its not just the Balance Leads (if they were bad), I think you guys are right... the Tab may have blown off. The total voltage is 11.7v for this 4s pack.

$75 (plus taxes and shipping) for a new multistar pack on Hobby King :x

Not to interested in opening up the pack and peeling the cell out.

One questions is, if the positive lead blew off, how am I able still charge it on my charger?

I did plug it into a battery monitor. Looks like the 4th cell is dead.
https://www.youtube.com/watch?v=Xb2dhc55J3o

 

[amigafan2003]

Have you tried a multimeter on the main wires - what voltage do you see?

Often if a charger is set to balance mode, it will only only detect the voltage of the pack by measuring via the balance leads - the negative lead and the last positive lead - in this case 11.79v. If you tried to charge it in non balance mode without the balance leads connected, it would probably see the whole pack voltage.

 

[mxer]

Agreed with above, check main voltage wires you'll soon see 15.76v.
Then replace 4th balance wire.

 

[fatbbq]

Looks more and more like the tab blew off on of the cells. I went out and bought a DMM.

The pack voltage is 12v (rounded up for simplicity). So one of the cell is dead.

Can I cut the red wire and charge it as a 3s pack?

 

[fatbbq]

You guys will hate me. I charged the pack anyways as a 3S pack. The last cell acts like a short.

Probably the last time I'll use this battery. Going to wait for a sale on this multistar pack

 

[Punx0r]

Thinking about it, it can't be a tab blown off otherwise the whole pack would be open-circuit (you'd measure 0V on the main battery leads). You somehow have one cell (the red balance one) gone short-circuit...