Is my battery junk?

[Paultro84]

I have a 4s lipo that isn't acting right. I set my charger to 5 amps, it's a 5200mah, but it will only charge at 3 amps. When I storage charge it, default setting is 1 amp and is not adjustable, it only takes .3 amps. With my 2- 3s batteries or my 2- 2s batteries it goes up to 5 amps until it's almost charged and then it starts to drop down. When running the Outcast and the LVC kicks in with the 2s or 3s batteries they're down to 3.4 volts faithfully. But the 4s pack drops down to between 3 volts and 3.2 volts. And when I charge it after the LVC and check each cell they're all different. 3v, 3.1v, 3.3v and 3.5 v. Should I just get rid of it?

 

[Jerry-rigged]

I am guessing your charger is a 50W charger? 50w / 14.4 = 3.4v. So the max amps a 50w charger can push to a 4s is 3.4. Plus as the pack voltage goes up, the amps will drop, down to around 2.6 before the balance cycle starts.

For charging 5000mah lipos, you need about 20w per cell, (plus a bit of "spare") and for larger packs, you need more power. For 4s charging, look for 100w-150w chargers, for 6s, look for 200w chargers. (this is watts per channel, not total watts. Watch for those 4-channel 200w chargers, that are still only 50w per channel)

 

[olds97_lss]

That's some really useful info @Jerry-rigged
I don't run into that issue with running 2S packs. It helps make sense why the "400w" (200w x 2) charger is rated at max 10A x 2 when only charging a 2S pack.

 

[Paultro84]

I am guessing your charger is a 50W charger? 50w / 14.4 = 3.4v. So the max amps a 50w charger can push to a 4s is 3.4. Plus as the pack voltage goes up, the amps will drop, down to around 2.6 before the balance cycle starts.

For charging 5000mah lipos, you need about 20w per cell, (plus a bit of "spare") and for larger packs, you need more power. For 4s charging, look for 100w-150w chargers, for 6s, look for 200w chargers. (this is watts per channel, not total watts. Watch for those 4-channel 200w chargers, that are still only 50w per channel)

My charger is only 80W per channel. :-(

 

[Paultro84]

Either way, the volts after being used bothers me. Why would all the cells be at a different voltages? Doesn't happen with my 2x2s packs or 2x3S packs after a run. And I understand what Jerry is saying but when I charge the 4s pack and I set it at 5 amps, it only harges at around 3 amps. But if I crank up the amps on the charger to 7 amps, the battery will take 5 amps. Which should be fine for a 5200mah. For laughs and who ha's I cranked it up to the max of 10 amps for a second to see what it would take and it was at 7.3 amps. I shut it right down. With my other batteries, they take 5 amps when I set it to 5 amps.

 

[Typhon]

Either way, the volts after being used bothers me. Why would all the cells be at a different voltages? Doesn't happen with my 2x2s packs or 2x3S packs after a run. And I understand what Jerry is saying but when I charge the 4s pack and I set it at 5 amps, it only harges at around 3 amps. But if I crank up the amps on the charger to 7 amps, the battery will take 5 amps. Which should be fine for a 5200mah. For laughs and who ha's I cranked it up to the max of 10 amps for a second to see what it would take and it was at 7.3 amps. I shut it right down. With my other batteries, they take 5 amps when I set it to 5 amps.

If your having irregular voltage after a balance charge then your pack might be going bad, either as a whole or individual cells. If your 4s is dropping down to 3 volts then thats too low and will damage them. Personally i don't beleive cells should dip below 3.4v. Stock blx lvc is garbage imo and shouldnt be trusted. Always use an external lvc alarm that you can set your voltage cutoff at. Their cheap and under $10. Extra safety imo to protect the expensive items. I set mine at 3.5v to 3.6v as under load it can dip lower than that and will give me an early alarm for a safety margin.

 

[arrmaracing]

When i was buying my charger i was told to get a charger that had a minimum of 80w per channel.