I use a 4000mah Geshi Ace 2S Lipo Pack which I got together with a second hand kit. I'm not sure what happened why it doesnt want to charge anymore but here's what went down:

The battery's balancer plug (the 2 black wires and 1 red wire) the red wire got disconnected from the plug while I was removing the lipo low voltage alarm from the pack (so I put it back - just a quick fix super glued the wire back on the leads).

The next day, I continued using the pack without charging cause the low voltage alarm showed all green lights. After around 30 minutes, the low voltage alarm went off on one of the cells so I tried charging it but the charger says there's a problem - it says one of the cells is 0V and the other one is 3.8V.

Did I discharge it completely? Or is it just a problem with the balancer plug?

Or did I just get an old pack that needs to be replaced already? It's probably less than a year old but more than 6 months (used in drift competitions from what I know)- how long do lipo batts last anyway?

Should I buy a new one or try re-soldering the wires on the balancer plug?

Help please!

Need to make sure the voltage is being indicated correctly from the balance plug. The charger uses that to decide if lipo is below safe level to charge which is usually about 6v. If balance connector is messed up, charger is seeing one cell as 0v which it may not really be. Regardless, the 0 and 3.8v from teh other is not above the safe charge level so the charger won't try and charge it.

Fix the balance lead and if you have a dvm, check the voltage yourself from the balance connection and see what voltage is for both cells. I doubt you've pulled one cell to zero - it would have puffed on you going that low. Need to fix the balance wiring and try charging again.

Another test is to see if the whole pack is reading 0 volts. If so it's likely a bad solder joint on one cell breaking the whole circuit. If one cell reads 3.8 and the other cell is truly dead, the pack as a whole should still read 3.8v.
Super glue is non-conductive so may actually be insulating the connection .

Yeah I'll try fixing the leads first I guess. Will give you updates as soon as it works!

Thanks guys!

It worked! Soldered the wire back on and it's now charging and reading the pack correctly! Thanks guys! Well I still bought another pack though just in case this old one looks like its about to go anytime.

Thats great, glad it worked out! That old lipo might surprise you, you never know how long one's going to last...