I just picked up a couple new aw 18650 batts today. I already have 6 in my rotation, should I add the 2 new ones in there or can I just put them "the drawer" till I need them? should I fully charge them before storing or just leave them with the factory charge on them. Thought it would be good to have a couple back ups just don't need them quite yet. But I don't want to ruin them either.... Suggestions?