I've noticed my voltage hovers around 3.8-4.1 volts. The specifications state the output voltage as 1-8 volts. I have tried different batteries, Efest 35 A, Sony VTC 30A, Samsung's, the voltage stays around 4.0. After searching around, other users have noticed the same thing. With a 4 volts, theoretically it would be impossible to achieve 70 watts. Curious what voltage other users are getting, and is anybody getting greater then 4 volts.