Okay, so I really need to slow down; I made a couple of bad assumptions, which I followed up and caught. I did not buy the parts on Sunday but just now. Here is where I fooked up.
#1 - My worry was right. According to the vendor, but he said that a 18-22V cannot be step up to 83V, which was my concern. I think what would happen in this case is that you just get a lot of heat and huge inefficiencies which would eventually make the converter go boom. But, he said I can step up 18-22V to 41-43V... And, I also saw a video review of the same converter on Amazon where a guy steps up 14V to 48V for his ebike batteries. So... I guess I would be changing the battery setup back to 36V (thank goodness for my modular battery setup) and basically cutting my power potential in half. I could try to test it at 83V and assume mebe the vendor was just being too safe but I dunno... At 36V nominal, it means I wont be at 3000W max continuous but at 1500W max continuous or closer to 1000-1200W, which is a little over 30 mph. Still decent but yeah I won't attempt to hit 50 mph now when I'm back at 36V and it is too cold now to even attempt 50 mph at 72V. Much later, I can try running two step up converters in series to go from 20V to 42V to 83V...
#2 - The video I linked and am reference uses a 33cc 2-stroke engine that had 4 mount holes at the bottom of the engine block. I assumed this was the same for 25cc. Nope, there are no engine mount holes on the bottom. I went to the hardware store (work there) and had a real good look and inspection of the 25cc. I think I can use the bottom front shaft screw hole and the back gas two screw holes as locators. I don't think they can serve as mounts as I think they are not engine block holes especially the two in the back, which just go to hard plastic. So, I will need to provide an additional clamp or straps to get it on the plate securely and resist vibrations.
In terms of the plan, Imma do the following over the next month or so so its ready to roll in mid March just in time for spring break where I can take off from work and if I am confident go on an epic tour.
- Test the 25cc motor operation - start up, choke, idle, rev ranges
- Assemble the generator setup
- Test the converter for voltage ranges, current, and memory (turn it off)
- Assemble the mounting plate on bike
- Test the generator and ebike only (no battery); make sure it runs
- Test entire system together for functionality
- Route generator throttle line to unused gear changer on handle bar and check power levels. This might not work; the throttle play in videos for the 25cc looks real twitchy. Ideally, I like to be able to set the generator power level from the handle bars and not have to stop and change the idle.