LightningRods wrote:Good catch! There is no freewheel between the rear wheel and motor. I did this initially to get more reduction. It occurred to me afterward that regenerative braking should be possible. I have the bike fitted with a controller that has adjustable regen. If the wheel shop ever gets my wheel back to me I'll let you know if and how it works.
My little RC motor is mounted to my swingarm and regens just fine. The chain setup really doesn't care which direction the power is flowing. Chain regen will only work if there is no spring loaded tensioner!
If there is a spring loaded tensioner then under regen the bottom chain will pull itself straight and all that slack will appear on top of the chain likely flinging it off. With no rear freewheel this is a terrifying thought. 219 chain is beast and will eat whatever is in its way. The hit of the regen would also be violent while it takes up the slack of the puny tensioner spring.
You could run a very solid but adjustable idler type chain tensioner that is not
spring loaded. This, having more travel than a horizontal dropout, also leaves you the option for drastic sprocket changes out in the wild.
Another solution would be a sliding rear axle plate dropout like motorcycles use with no other tensioner.
Yet another solution could be a larger diameter hub axle that is machined with 2 flats for a clamping style dropout to hold onto. Problem there is you need pretty long clamping style dropouts and its still anybody's guess if they would keep the axle from sliding.
You could also take up the slack with a sliding front motor mount. Bottom line is the tensioner has to be static because under regen it is dealing with a lot of force. We don't commonly see idlers on the tight side of the chain for a reason.
Unfortunately, any of these static tension methods require really precise sprockets. Once its all rigid the imperfections in the sprockets show up as drastically different tension during every revolution. I bought some cheap 3/4" bore kart sprockets and designed around them and now I wish I hadn't. My front sprocket is so bad that there is probably a link worth of slop in one revolution. Its really annoying and induces a terrifying vibration at speed. I also have to make sure its at the tightest point when I adjust the chain tension or it will bend something when it rotates around. Probably need to go to those $30-40 ones that the high end shifter karts use
So chain drive regen is totally possible but there are a few little design hiccups.