Lt_JimDangle

So my battery has been charging for about 1 hr and 20 minutes its a 4s 5000 mah gens ace im balance charging it and all cells are at 4.20v but one is at 4.13 and my charger isnt done charging but also isn't charging any amps! So is this bad or should i just let it keep going?

Maj_Overdrive

My Feedback: (11)

This can happen sometimes depending on the battery and the capabilities and algorithms of the charger. The charger is trying to discharge 3 cells and charge one at the same time. Doesn't always work out since it charges through the main leads and usually only discharges through the balance leads. The fact that each of the balance wires are connected to the positive of one battery and the negative of another doesn't help as it will effect the other battery.

My recommendation is to just run the pack as is. Don't run it until it hits the cutoff though, run about halfway, then try charging again. If you see that the cell still remains a lot lower then you'll need to charge that cell indivually through the balance connector. Use a multimeter on the balance connector to find which wires are for that cell. Then use a hobby knife or something small to depress the little tabs on the metal part of the connector to pull the metal part out of the plastic housing. Hook it up to the main leads of your charger (make sure polarity is correct and that there's no chance of the + and - touching) set the charger for 1s and charge until the cell is slightly above the others. Monitor the charge and don't walk away as it shouldn't take long. Once it's a little above stop charging, reassemble the balance connector and charge like normal. I've done this truck a few times with different packs and didn't have it repeat unless the pack sat for an extended period of time. But it should still be monitored and if it happens again it could indicate the cell is on its way out.

collector1231

My Feedback: (1)

I agree to what Maj said. I'd also possibly even try to bump it on NiCD or NiMH mode. Thats what I do to cells with a crazy cell and it can normalize it.

Maj_Overdrive

My Feedback: (11)

In the case of having a low cell like this, sometimes charging in NiCd or NiMh mode can help bring it back. Obviously you don't want to use NiMh mode when the pack is basically fully charged though as the balancer doesn't work in NiMh mode and won't prevent the higher voltage cells from being overcharged. So run the pack down before charging in NiMh mode and stop the charge every minute or two to check the voltages. You may have to go through a couple cycles with the NiMh trick though depending on how far out the cell is.

If you charge the cell individually as a 1s lipo, you can do it on a pack where all the other cells are fully charged. It's not something you use very often but balance connector pig tails are pretty cheap so you won't have to take apart the balance connector to charge an individual cell. I bought a couple extras when I made up my different charging harnesses.