Petrol Electric Hybrid

[Torchy]

Having just finished one project and close to finishing a second I'm pondering the build of a petrol/electric hybrid motor cycle. While this is only an idle thought at the moment my 'idle thoughts' do have a habit of ending up in the workshop. My current thinking, as this will be a steep learning curve is to start with a 125cc motorbike and then add some electric power. Has anyone done this? or if you have any constructive ideas I would love to hear from you? I have a small well equiped workshop and experience of creating prototype parts.

 

[Eastwood]

Honestly, I think it’s a bad idea simply because of weight. You’re going to have the weight of a combustion motor plus the weight of the battery? You would end up with a very heavy 125cc motorbike. The whole purpose of riding a 125 cc would be because it’s Light in nimble.

 

[fechter]

I sort of recall some attempts at this in the past but can't find them.
With a stock petrol bike, there won't be much room to add the electric stuff, especially the battery. One approach would be to use a big hub motor on the rear wheel and some very high rate batteries to give some extra power for acceleration, then use the motor as a generator to recharge the batteries during lower load periods. The control circuit will be the tricky part.

 

[Torchy]

Thanks for the comments, I'm not particularly bothered by the weight, firstly I'm a lightweight and secondly my motorcycling knowledge over many years leads me to believe that I can double the power to weight ratio of the original bike. You are correct in assuming that a battery pack will take some thought but my thinking is to use several smaller battery packs hidden in the the numerous gaps around the bike. Hub motors would seem to be a good choice, possibly front and back and I don't see a problem making alterations and adaptions as required. Getting a smooth power delivery with potentially three power sources could be my biggest challenge. Unfortunately I no long have access to the electronics guru who I have used in past projects.

 

[A-DamW]

I have sometimes wondered if you could remove the flywheel/magneto assembly and replace it with a high performance BLDC or IPM motor.
Coupled to some high C rate lipo and/or ultracapacitors and perhaps a VESC controller I don't see why it would not work.

 

[Torchy]

I have sometimes wondered if you could remove the flywheel/magneto assembly and replace it with a high performance BLDC or IPM motor.

That's an interesting idea.