So I'm going to buy a GGTS with an avs. I'm a little lost when it comes to batteries and chargers. correct me if I'm wrong but would I need a different charger for a 3v battery and a 3.7v battery? I really want to try 6v, not sure about anything higher just yet. I know 3.7v will be an everyday vape, but on occasion I will fancy a higher vape. Obviously as you can understand it isn't so cheap to get one of these and dont want to needlessly spend money on extra equipment if I don't need it. thanks 