Someone double check this quickly please

[GeeReg]

I just need someone to check this quick as I'm new to lipos. I just got 2 lipo packs to run in my Nitro MT. They are 2200mah 3S2P. To charge these I want to make a harness to run them in parallel to my charger, and charge at 4.4a right? TIA.

[squeeforever]

Yes. Just make sure to balance them.

[GeeReg]

So is it a better idea to charge them separately with the balancer for the first time?

[Gustav]

I'd say so,i sometimes charge 2 packs together to about 90%,then charge them to full individually attached to a balancer.The good thing about Lipos is you can charge them the night before.I sometimes run mine days after the charge,i just check them on the charger before i run them.

[GeeReg]

Ok thanks guys. I balanced both with my LBA6. One didn't need any and the other took about 2 min.

[jhautz]

If you are going to charge both packs together in parallel, they need to be balanced to each other as well. Make sure the voltage of the 2 ballanced packs is exactly the same before you charge them in parallel.

[GeeReg]

Well I charged them but I have a question. When the charge was over it had run for 68 minutes, but only took ~2000mah. After the cells reach 12.6v, the amperage tapers off but it continues charging. Is this normal?

[BrianG]

Yup, that's how Lithium charging works. The first stage when the current is constant, but the voltage steadily goes up is the "constant current" mode. The voltage will increase until the pack reaches 4.2v per cell (you are charging a 3s pack right?). Then, the charger switches to constant voltage mode where the voltage is constant and the current steadily decreases until it gets close to 0 amps.

In comparison, NiCD/NiMH uses a constant current mode for the full charge, but uses the fact that the voltage will hit a peak and then start dropping on its own to determine when to stop.

[GeeReg]

Thanks, I'd read about it but wasn't sure. It just seems strange that it takes over an hour to charge a half-dead pack. I'd just assumed that since you charge at 1C, it would always take an hour for a full charge from dead.

[SpEEdyBL]

You don't need to fully charge a lipo pack. In fact it's better not to. Just unplug it when it reaches 4.2 volts/cell volts. That is usually when it's 90% full.