To do the math I use electrical laws I learned a long time ago. (Ohm’s Law and Watts Law) you can do a search to find a web page that will do the math for you if you are not familiar with them. All you do is fill in the spec’s you do have (Volts, amps watts or resistance) and it will give you the answer. It takes some basic electronic understanding to know what to ask it and what the answer means.


The mini-fridge I have is small 8 inches square by 14-inches tall. It draws 4 ¼ amps. That’s 51 watts (12-volts times 4.25 amps = 51 watts) But when hooked up to a running car it gets 13.8 volts from the alternator output. That pushes the watts up to 62 watts. As it would with a solar panel as they are over-ranged to make up for lack of sun and the load put on the panel. So I would guess that my mini-fridge would need a 75 watt panel (100 watt would be a lot better) to run the fridge. $800.00 for a solar panel to run a cooler that can only hold 6 cans of pop is kinda expensive for most people.