> This makes me wonder how accurate float bulb based fuel level sensors really are. They aren't. On light aircraft, the only thing they're good for is as a dou

> This makes me wonder how accurate float bulb based fuel level sensors really are. They aren't. On light aircraft, the only thing they're good for is as a double check on a manual fuel reading (using a dipstick) or a time-based calculation, and to confirm during flight that the fuel cap wasn't left off. Beyond that, the needles bounce around so much during flight the only thing you can really verify is "yes there's some liquid there; somewhere between empty and full". Many light aircraft owners have since retrofitted "fuel totalizers" which measure fuel consumption, and are manually reset by the pilot to a dipstick value when fuel is added. My group aircraft's fuel totalizer seems accurate to within at least about 10%. It can be calibrated better, but manual dipstick readings are only accurate to a couple of gallons anyway. However, one key difference is that I do know, to within about half an hour, my fuel endurance before departure. I'd want the same from a battery.