New Guy with a New Truck

I was just curious about something. If it was the charger, why would one battery charge fine, and then the other be sa far off. it almost leads me to believe there may be a weak cell in the pack. i know it shouldnt charge over 4.2 to a cell but is it possible it only was a cut off for 8.4V instead of the 4.2V per cell? It has never gone above 8.4v. These packs are rather cheap, so i was thinking that they may be the problem. although they run the truck very nicely.

[Steeni]

Well, you're right if you're assuming that only the overall voltage counts as cutoff, means 8.4 V for a 2s Lipo pack. Your problem is the fact that on your "bad" pack a cell seemed to have drifted a little too far out for your built in balancer to be able to balance it out when charging at full rate.

Here's my tip: Charge that pack with only 0.1 C. That means if your pack is rated at 5000 mAh, then go charge the faulty pack with only 0.5 A instead of the 5A you would normally use. That way it would take about 10 hours to fully load your pack but it leaves your balancer with plenty of time to balance your cells out. Rince and repeat and after 3-4 times charging it that way your cells should be good enough to be charged normaly again.

If your problem persists after 5 times loading your pack with 0.1 C, I'm afraid that a cell or, and that's far more often the case, the internal wiring of your pack is faulty.

Originally Posted by Steeni

Here's my tip: Charge that pack with only 0.1 C. That means if your pack is rated at 5000 mAh, then go charge the faulty pack with only 0.5 A instead of the 5A you would normally use. That way it would take about 10 hours to fully load your pack but it leaves your balancer with plenty of time to balance your cells out. Rince and repeat and after 3-4 times charging it that way your cells should be good enough to be charged normaly again.

Hey guys thanks for all the tips. ill have to try those pinions next. truth be told im hoping the stock one hangs on cause i like the way its geared as is, but stuff always breaks. Im gonna take your advice on charging it at .1C but will it be ok unattended? i dont know if i could sit there for 10 hours lol. 30 mins is one thing. by rinse do you mean run the pack in the truck? before i charge the pack at .1c should i maybe put the pack to storage mode? Once again i appreciate the input you guys do know your stuff. and if the lipo is done for ill just order some more. maybe 3 this time and hope for all good ones and side line the problem pack.