Now for the batteries you are using frequently NEVER keep on charger for longer than needed! If your charger turns from red to green when charge is finished like mine does, remove it from the charger as soon as you can. A few extra minutes once in a while doesn’t seem too crucial but hours after can kill them. Also same goes for when it dies, however you don’t want it to drain too much. My Green Smoke stops working and flashes at the tip I know I need to remove the cartridge to recharge it fairly soon is best, if you wait a week it might be killing the battery unless you charge it at least for 30 minutes before you stop using it. It is kind of a pain to deal with them but you get used to it once you develop a cycle that works and doesn’t hurt the battery. As far as battery cost’s yes a little bit pricey but I have the 2 I originally got in my kit, one short and one long, and since I have used this careful charging method I just explained I have no problems now for past 3 months of using them both switching between the 2 frequently. Even if one or both die soon in another month or less even I will still be saving money from normal smokes because I am already saving about $75 a month.