Sorry if this explination is a bit long. I figure I need to provide some context for my question.
I'm working on a school project for a class. First I'd like to mention this is all hypothetical I won't actually have to do anything so things like saftey aren't really my concern in this case. As long as it should work it's fine.
Anyway in this project I need to power a satelite for 97 minutes using two power lines at 12v at 30 A and 5 V at 45A. I have a 1987 ford pick up with a v8 engine. After doing research I found this was most likely it's engine Ford 302 V8 (5.0L) | Specs & History
The pickup in this senario has no battery, transmission, or rear wheels.
In the area is also a 35Kw disel generator.
However I have no disel or gasoline for that matter. What I do have though is a propane gas grill and several 20# propane tanks.
So my plan is to take out the electrical generator from the disel generator, attach it to the crank shaft of the 302 (basically the gas engine is replacing the disel one) and then use the truck's alternator to get my 12v at 30 amps and use the generator's output to get my 5 v at 45 amps.
I have a few things I need to figure out but the thing that I made this thread to ask for is how much propane will I eat through in 97 minutes? I've done research and if I'm optimistic and generous I should be able to say the engine will eat about 20 MPG. Since propane produces 25% less energy and you need that much more to get the same power as gas than I can assume I'd get 25 MPG with the propane.
Assuming my assumptions are okay how do I turn that number into a time figure? Do I need to figure what RPM the engine will be running at?