I'm thinking about getting my wife one and was wondering if anyone has used these and what their thoughts are on them. Also what are the best 18350's to use for longest battery life, I already have a couple EH 900mah IMR's. She'll go 2 days using an 1100mah ego-c upgrade between charges, how do you think the ZMax will do with these batteries or should I get a couple new ones? Thanks for the help!!