50% +, using Kelly Controller, Grinhill like setup with roadbike. Measured multiple times up to top of Old La Honda Road, Skyline and returning down Kings Mountain.
Outstanding! I take it you pedal a lot, so some of that regen is recovering some of your human effort especially on the trip back down. Regardless, that's strong. Push for 60^ on a round trip, and then try the same route with no pedaling and let us know the difference.
I'm not sure why JonesCG and Kingfish think regen% isn't meaningful. Sure it can fluctuate wildly early in a ride, especially when starting from an elevated point. Total electric energy sent back to the battery by regen divided by the energy sent from the battery sounds like a meaningful number to me.
If you have a programmable controller, then regen can be tuned pretty broadly via a combination of hi/low in the pgm settings and shunt modification. A shunt mod fools the controller regen current limit just like it fools the regular current limits, and then you use program setting for current limits to get back to where you want. In your case, you'd want to try low first, and if the braking force still tool strong, you'd need to increase shunt resistance instead of the more typical reduction to get higher current.
For those with variable regen,
Is that controller specific, or something we can do with more common controllers. Somehow I missed how to accomplish that, and while I love my soft smooth regen, if I could vary it in a controlled manner at the handlebars that would be even better. I'd love to use the mechanical brakes even less than I do.