John in CR » Aug 22 2020 7:10am
Balmorhea wrote: ↑Aug 22 2020 12:13am
John in CR wrote: ↑Aug 21 2020 11:22pm
To me riding an ebike that is used at full throttle all the time makes no sense. Would you ever purchase a car with such low performance? Why not be able to do the speed limit up hills or into headwinds?
Cruising at full throttle at the desired cruising speed (for electric bicycles with 250-1500W) means cruising in the most efficient, coolest running part of the power curve.
It also means having the most torque available to climb, or jump off the line, for any given controller. Higher top speed comes with lower low-end torque.
Those statements are not necessarily true, but for every situation they are true I can make the same happen at 80% throttle using the same motor as well as with a differently wound version of the same motor. The problem is that you continue to insist on essentially the same thing using different wording.
Balmorhea wrote: ↑Aug 22 2020 12:13am
My primary e-bike has 48V x 35A of power available, but tops out between 18 and 22 mph depending on state of charge. That means it cruises extremely efficiently, but it also picks up power and torque immediately when loaded with an uphill grade or a headwind. It climbs the steepest grades I regularly encounter at about 15 mph and 1600-1800 watts, while barely getting warm. I wouldn't swap for a motor that tops out at a higher speed but climbs worse. What would be the point? It's a bicycle, not a motorcycle.
You conveniently left out that you slow down for every puff of wind or slightest incline, not to mention being screwed when you're stuck behind a dump truck doing 12mph up that hill.
FYI, since you commonly talk about torque and power like they're 2 separate things when power = torque X rpm. A given load whether it's overcoming gravity up a hill, or increase in wind load, or extra rolling resistance from more weight carried requires the same power for a given speed, and (assuming same copper fill) any variation of a motor can achieve the same results. In addition, our controllers are so good at feeding our motors that differences in throttle position to achieve the same rpm makes negligible difference.
If it wasn't for the extra rolling resistance of my chosen tires, my primary ebikes would cruise at your speeds more efficiently on the flats and definitely climb and accelerate much better, yet they have 3-5 times higher top speed. That's because the design is more efficient and has nothing to do with Kv.