just a few weeks into our 510 units, my wife uses hers constantly while watching tv, I use mine maybe every half hour for a few drags,,her battery will go out by the end of the night, mine wont, Now is just a few hours of use enough to drain the battery ? She doesnt like the bigger heavier units(ego?) Is there a battery the next step up from the 510 that is similar in size and weight and has a longer life? We are charging her e-cig every night befpre bed, is this normal ? thanks as always for the help