Having lots of time lately, while recovering from a recent surgery, i began to look into the possibility of using the energy stored in an air tank to spin a simple GM alternator.
I began looking into using DC powered compressors and found ready made 12VDC at 20 amps max, 200 psi air compressors already mounted to a tank.
If I attach small blades around the outer edge of a 26″ bicycle rim(pelton wheel) and mount it on an axle through a bearing with an identical 26″ bicycle rim, I can release the stored energy in the tank to spin both wheels.
Run a belt around the second 26″ rim and down to the alternator with the 3″ pulley. 800 rpm at the rims = over 6400 rpm at the alternator.
Mount volt sensing wire near battery to keep system at optimum voltage and to handle load as compressor kicks on.
Alternator that is designed to withstand high engine temperatures should be fine as long as high-pressure air from the tank is hitting the blades on the first 26″ rim.
No magic or perpetual motion, just using the energy stored in the air tank to do the mechanical work of spinning the alternator. Use 4 nozzles made from small pipes with the ends pinched. Roughly 4 cfm @ 90 psi for example, would = 29.92 gpm @ 207′ head.