Starving ("dropping") the Regen bike
What should become obvious about this last example is that when power input is limited the freewheel bike can in effect "starve" the regen bike by using enough power to force the regen bike to fall behind. (in effect you are forcing the regen bike to become "dropped" since it can't catch up)
The regen bike uses it's maximum power (1000 watts input) up the hill.
The freewheel bike uses just 507 watts input to make it up the hill. (480 watts in the example below)
...in this scenario the freewheel "wins" because it never gets lazy.
The "Hare" in the story only loses because it gets so lazy as to allow the "Tortoise" to catch up and pass while it was sleeping...
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Back To The Original
This goes back to the default values. The freewheel is allowed to go just fast enough to "starve" the regen bike that is limited to 1000 watts. The default weight is used on this. (I thought this might make it easier because we've done these numbers already)
Downhill (5% negative slope for 10 miles)
Freewheel - 10 miles / 24.35 mph = 0.41 hours (net power gain/loss is zero)
Regen - 10 miles / 15.00 mph = 0.67 hours (behind by 0.26 hours)
Recaptured Energy = 0.133 hp * 746 watt = 99.22 watt
99.22 watt * 0.67 hours = 66.48 Wh * 0.7 (motor losses) = 46.5 Wh
46.5 Wh * 0.9 (battery losses) = 42 Wh (this is the energy recovered)
Uphill (5% positive slope for 10 miles)
Freewheel - 10 miles / 14.7 mph = 0.68 hours
Power Needed - 0.451 hp * 746 watt/hp = 336 watt / 0.7 (motor losses) = 480 watt
480 watt * 0.68 hours = 326 Wh
Regen - Must do 10 miles in 0.68 hours - 0.26 hours = 0.42 hours (or less)
10 miles / 23.89 mph = 0.42 hours
Maximum input power - 0.938 hp * 746 watt/hp = 700 watt / 0.7 (motor losses) = 1000 watt
1000 watt * 0.42 hours = 420 Wh
...but we get to subtract the "savings" so the actual value is:
420 Wh - 42 Wh = 378 Wh
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The "smart" freewheel rider goes fast enough to never let the regen bike back into the race...
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As long as the (Hare) freewheel bike doesn't get "lazy" the (Tortoise) regen never gets a chance to catch up.
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Last edited by safe; 02-09-09 at 11:51 AM.