[Glowing Bits!]

There's one beauty to lithiums, they tend to run pretty much at full capacity then fall off a cliff when drained, unlike other battery types.
For charging, it needs to be balanced.
Depending on what the OP plans to do, wouldn't it be a better idea to source a flat type lithium pack, as found in model aircraft?
Chargers for these packs are readily available, plug and charge!
Just a thought anyhows.