Charging from a vehicle's cigarette lighter with 12V battery system. Please ensure the power consumption is less than 300W, if your devices power consumption exceeds 300W, the generator will automatically shut off. 1x ALLPOWERS Portable Power Supply. To calculate how long would it power your device, you need to know the watt of your device, and please consider the wire resistance and wastage of energy, the following is the optimal condition. If your laptop is 45 watt, Conversion rate is about 80%, so the running time=(200Wh/45w)80%=3.6hrs.
If your devices is 12V 5A input, the running time=200Wh/(12vx5a)80%=2.6hrs. If your cell phones battery is 2000mAh, the running time is 200Wh/(2Ax3.7V)80%=21times.