The only fuel cell cars I have been involved with, we checked fuel level with a ruler. How is it done with SRF

When the cell is empty, the car stops going.. Which is probably why pretty much everybody has a "running out of fuel" story of some sort.

When we get a car, we pump it dry to see how much the usable capacity is, then usually fill them up, and keep track of the time they are on track using the old 10 min. / gallon rule of thumb.

If you really wanted to be fussy about it, you could weigh the car (assuming you know how much it weighs empty or full).

Dave

Dave