This means that it consumes 20 Wh for every minute that it is left on. If the oven was on for 5 minutes, then multiply 20 by 5 and the result is a total power consumption of 100 Wh per use. If your electricity rate is $0.10 USD/kWh then the cost of that is $0.10. 100 Wh = 0.1 kWh.. Solar Panels power generation is commonly given in Watts e.g. 120 Watts. To calculate the energy it can supply the battery with, divide the Watts by the Voltage of the Solar Panel. 120 Watts / 18v = 6.6 Amps. Please note that Solar Panels are not 12v, I repeat Solar Panels are not 12v. It runs 2 laptops and a battery charger. This is coupled with 2 35 amp batteries (70 amps) and 6 100 watts solar panels. I know I'm solar panels high, but I expect to upgrade the power inverter to at least 1000 watts or 2000 watts continuous (if I use a compact freezer) and 100 watt agm for fan cooling operations. "/>How many amps does a kettle use