Can I double my batteries to double the power? or will that simply double the mAh and time between charging? Do I parallel or series? How do I parallel or series? I have a 2xAA box mod, but I want to double the volts for my dccs, while I'm waiting for my vv 3xAA box mod. I don't have room for another batt, but I'll tape it to the box if I have to, just want to try 7.4volts. Any suggestions?