Re: How long can you run a box fan on the power outlet?
The big problem with what you are proposing is the extent to which you drain the battery. Even in deep cycle batteries, which this isn't, there's a percentage of depletion that you shouldn't pass or you will damage the battery. So as was mentioned before, don't let it drop too many volts. so yeah, get a honda inverter or a HFT predator for 40% of the price. You could also get a couple deep cycle batteries and an inverter and run that box fan as much as you want.