I want to run a coolbox in my campervan that has a 12v leisure battery.
The given wattage is 35w
It would be plugged into an inverter that provides 230v and has roughly 85% efficiency
How should I calculate the amp usage so I can judge the amount of time I can run the fridge from my battery?
a) (35W/230V)*/0.85
giving 0.18 Amps
b) (35W/12V)*/0.85
givig 3.4 Amps
c) ???