Hybrid Electric Bike?

[Ride_Red]

Is it possible for a battery to power a mid-drive motor while simultaneously receiving a charge from a hub mounted motor in "regen" mode?
I have a bafang mid drive engine from Luna Cycle and a two-stroke friction drive engine mounted on the rear wheel for street driving which gives me a faster takeoff and more top end. I was wondering if an additional hub motor could be used for regenerative charging either from braking and/or by varying the level of regen from the hub motor when in motion?

 

[MadRhino]

It can, but it is a deficit. I mean, the hub will consume more power than it will regen, and even when not used for regen, will continue to consume power by its weight and resistance.

 

[amberwolf]

As MadRhino notes, it's going to take (significantly) more power to move the bike than you can recover; you're just going to waste power doing this.

It may not be obvious, but there are a lot of losses in every system, so you can never get back out of one what you put into it.

If you're intending to run the motor in regen mode all the time to generate power from the drive system, you might as well just not put any motors at all on the bike, and just pedal it around, because that's more efficient and a lot cheaper.

Otherwise, you're just wasting power trying to push the bike down the road, generating heat in both motors and the controllers, etc., and you'll have to pedal probably harder than you would if it was a pedal-only bike just to break even.



If you want more info, there's a bunch of threads, mostly in the Alternative Energy subforum, about people trying to make perpetual motion machines like this; they can't work. You can probably find some of them just by searching for "perpetual motion".

https://endless-sphere.com/forums/search.php?keywords=%22perpetual+motion%22&terms=all&author=&fid[]=40&sc=1&sf=all&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search

 

[dogman dan]

The idea would sort of make sense to me, though very inefficient as they say above, if you had only one electric motor on the bike, a hub motor. Adding another now would just be a lot more weight for little benefit.

But a gasser/hubmotor hybrid is not a new idea, and it does work well for some. But not really so much for re charge, just for the braking that does not wear out pads. Even with that setup, best to just run gas with no regen turned on when you run out of juice. Better than pushing the gas engine so hard making it push regen for the several hours it takes to recharge. In generating mode, that hub motor will resist a lot, making your gas range shorten a lot, for not that much electric range put in. not really worth it.


It sounds to me like your bike is near perfect now, other than you might like a larger capacity battery at some point.