... Ipad 5200mah monocrystal silicon portable solar charger Technical Parameter1.Solar panel:5.5 V,3W 2.Solar conversion efficiency above 17%3. ... built-in is about 7-10 hours. Function Brief 1,Intellectual charging function: precharge,constant current charge,constant voltage ... 3,PWM control the constant voltage.4,Auto protection function:overcharge,over discharge,overload,reverse connection,short-cercuit ...