I know it's different on the 10s, but the 4s charged directly through the balance plug, and charged each cell by itself completely independent. I've seen as much as a 3c charge rate on my 4s, but it never lets the pack get even warm. Nifty.

Here is the manual on the 10s. It's on my shopping list just as soon as budget allows.

http://www.fmadirect.com/support_docs/item_1258.pdf

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