2stroke hybrid

I'd say about half way. The best set up I've seen used a honda generator, a less polluting, longer lasting 4 stroke. The latest model puts out 1000 watts of 120v ac and weighs about 50 pounds. A golf cart charger, about 15 amps, plugs into that. With that, you can pretty much run on a set of sla batteries, charging as you go for infinity. But it still won't let you turn off and run silent since the charger will provide slighlty less power than you are using.

To charge a dead pack and ride would take a bigger generator, more weight, etc. The other thing is, can your hubmotor run continuously for 80 miles? The designers assume you have a battery that runs down in 20 miles or less. So you may want to look at motors that have air cooling fans and use a chain drive design.

Once you build your magic generator that takes 500 watts of mechanical imput power and turns it into 2000 watts of electric power, can I be your partner and sell it to the world?

Some smarter than I folks have kicked this idea around on another forum last summer, and lighter generators can be built. But they won't put out the power you describe, charging while riding. The big issue is the weight, as you point out. When I tried it on a trike with a 36v motor, my 100 pound generator slowed my speed by 50%.

If you just want to build a generator that puts out 500 watts of 36v dc to power but not charge at the same time, that is another story. The others thought it might be doable at about 25 pounds.

The one case I have seen, actually doing it, sucessfully, was using the lightest honda generator and a golf cart charger. So that is the starting point, this works. Surely it can be improved on, but that method is not so bad, the generator and charger can be removed when not needed, and it runs pretty quiet with far less pollution than any two stroke. I think that method has a lot to offer, using a trailer to carry it so you just have a regular ebike most of the time.

On the motor, something like the cylone is what I was thinking, or even something more powerfull so it can run pulling a lot of weight for a long distance without melting down. The real problem with your plan is if you get too heavy, the motor may not want to go that far without overheating. Another option is a crystalyte 530x type motor. They are pretty powerfull, and can go long ranges if ridden smart. Justin rode one across the entire width of Canada. Maybe you just need to monitor temperatues and stop a few times to let the motor cool.

One of the conclusions arrived at discussing this last summer, was that in most cases, it was a lot more practical to simply carry more battery than to try to build a generator. Not cheaper, just more likely to reliably get you there. One of the reasons for this conclusion was that range you could get from 25 more pounds of lifepo4. But somebody has to do it, and prove us armchair experts wrong, so why not you? good luck and have fun!