One part of Friday's commute was a bit of fun. The first part of this commute is an 11% grade going up, and there was a lot of traffic right at 5pm so I sprinted up at full throttle and essentially kept up with traffic at 20 mph. Some folks seem to think that adding the pedaling input to 3 or 4 kilowatts motor input power doesn't matter, but my experience is that pedaling hard on a steep climb makes a big difference. If I don't pedal on this hill the speed is a lot lower (though I've never done it with zero pedaling so I'm not sure how low it goes, but likely about 10 mph).
One issue is how much power can we add for a short sprint? Some say 100 watts, but that's a long term number. According to various charts the upper limit short term is more like 1500 watts for an athlete, and 900 watts for a "healthy man" (though this drops to 450/300W for 2 minutes). The "healthy man" can do 200 watts for almost an hour. This is a far cry from 100 watts!
Another issue is what difference does this make. If you do this on the level where the motor is efficient it doesn't make too much difference in the speed. Pedaling hard when the motor is voltage limited causes the entire workload to be transferred to the pedals, and at 20 or more MPH this is more power than the rider can add, so only a few MPH can be pedal-added. But if you pedal on the steep grades where the motor torque is struggling and the speed and efficiency are low, adding the pedaling power can move the operating point up the efficiency curve significantly. The power from the motor is generating enough relatively constant torque and thrust to "flatten" the hill, and the pedaling you add then effectively is as though you were pedaling a non powered bike on flat ground. So the electric by itself may only get to 5 or 10 miles per hour on this gradient, but you can sprint pedal that up to 15 or 20 mph.
I pedaled pretty hard, as I wake up this morning 1.5 days later I'm feeling it. Probably shouldn't pedal quite that hard.
Looking forward to getting my Greyborg and Cromotor on that hill at 7kw.
Maybe I'll need to learn to pedal backwards just for fun...
The Cromotor has sufficient torque that it doesn't slow down much on hills. So pedaling won't help much then.