I am still trying to figure out all the batteries that are out there. So with all these new mini 30 watt devices coming out and if I stay at .5 ohms and above as far as coils go what are the best batteries to get. I have the purple efest 2500 mah 35A but it does not seem to last long. What other options would you recommend since the sonys are no longer available. What other batteries would work in these devices to work .5 ohm coils and above. Namely the Atlantis .5 and Subtank .5 coils? Using these on the cloupor mini and ipv mini.