[DutchmenSport]

Are you sure yours is a 12 volt fan? Mine is definitely 120 volt AC. I just went out and killed power from the electric pole and tried the fan. Nothing. I then flipped on the inverter and still, nothing. Plugged back into the power pole, and working again. The battery in my 5er is good.

I also checked to see if there was label on the fan with a name or manufacturer. Nope, nothing. I then checked my original paperwork to see if there was any documentation on the fan. Nope, nothing.

Unless yours has a built in timer, I know of no reason why it should stop running after a few minutes unless there is a built in safety switch to shut the fan off if the voltage drops too low from the battery, as an attempt to save battery power. But, I really don't know. So you might check to see how strong your battery is. Just kill power from the electric pole and flip on any house light. See how quickly it dims down. If it dims down quick, you are having problems with your batter. I'm just guessing here, assuming yours really is a 12 volt DC fan.