I don't think that a pusher or generator trailer has to have the power output of a full sized car engine. Most cars use an average of about 15 to 20hp to drive down the road. So if I charged up and took off with a 20hp trailer that might make the vehicle have practically a limitless range. Now I could also go with less, like 10hp. That would basically double the range. It would mean I'd be using around 10hp average from the electric drive train instead of 20hp average. And if I run out of electricity then the 10 or 20hp could be used to limp my way to a nearby place where I could charge.
I have a couple ideas. One would be to make a Hampson-Linde cycle air liquifier or two. One to liquify air and another to take boiled off nitrogen and liquify it so as to have pure liquid nitrogen. Then I'd have to get a large dwark flask for storing it. They make 55L models for under $1000. Then of course a pump that can work at cryogenic temps, and a large Gask motor or two. They make a 9hp unit that costs around $1500. So I'm thinking that for under $5000 I could have a little trailer that runs off of liquid nitrogen and gets me twice the range in an EV like the Leaf.
But then what if I run out of liquid nitrogen.
So that's why I was thinking of the stirling engine. I could make the stirling engine run off of liquid nitrogen, or any heat/cold sorce, like propane, bio-diesel. etc. Of course I'd have to completely fabricate the engine. I'm thiniking a 4 cylinder alpha cycle stirling engine that drives a swashplate.
