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Help choosing a bike upgrade
- Thread starter Gecko6090
- Start date
Not sure what you mean, but I see a real world torque advantage over the entire torque curve with System B, when only the battery input voltage to the system was increased. Are you saying that torque advantage is not there?
Doesn't matter. Neither was changed between system A and B.
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The example above:
Motor Simulator - Tools
Our ebike motor simulator allows you to easily simulate the different performance characteristics of different ebike setups - with a wide selection of hub motors modeled, and the ability to add custom batteries and controllers and set a wide variety of vehicle parameters you'll be able to see...
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stancecoke
Minor legend
30.1 = 51.1?! 
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I said the controller phase current. You can buy a controller or a battery. Controller didn't change. Battery did. Again, between the two systems, only the battery voltage changed, and now there's more torque. Why didn't it stay the same?
ZeroEm
Minor legend
Think he need a throttle! That is what is used for short bursts.
Old memories coming back of discussions of torque vs power that went on for years and years. "amps vs volts"
Old memories coming back of discussions of torque vs power that went on for years and years. "amps vs volts"
Folks talk about torque in terms of maximum torque. But torque changes over the operating range, so when people say they need more torque, it's rarely the off the line maximum torque (that drops like a rock as speed increases), but somewhere in the range that they ride their bikes in. Raising current will increase torque on the lower end, but the still drops to the same point when the top speed is achieved (no more useable torque). Increasing voltage shifts the torque curve to higher speeds, so even though the curve is still descending, at the same speeds, torque will be much greater. Out on the road, that's what counts more, for safety.
For a hub motor, you want the torque where the motor is still spinning efficiently. The low RPM torque is less useable since the motor will cook itself, so you want more torque at the OP's climbing speed.
stancecoke
Minor legend
Again, this is not because of the voltage, but because of the current limitations of the controller and doesn't help the thread opener. Only in zone C of this chart, a higher voltage helps. In zone A the controller cuts the motor current, in zone B the controller cuts the battery current.
If you keep the hubmotor and the controller, the system will fail at the same ascent with a 72V battery as with a 36V battery. With a middrive you can just choose a lower gear to increase the torque on the wheel.
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Agreed (on the mid drive) ! I’m actually starting to enjoy climbing slowly. It adds a lot of time getting to the trail head, but the leisurely pace is more relaxing. Having to shift a bit annoying, but not too bad. The section the OP is dealing with looks to be about one city block at over 20%, so that’s a quick downshift and climb.
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ZeroEm
Minor legend
Got it years ago, own the slowest Leafmotor on this site or does anyone have slower than a 7T. Run it at 72V mid range torque.
After testing voltage levels between 14s and 22s, my conclusion is if you want good acceleration between 20-30, for example, you need to go up in voltage and build at least a 40mph bike. No amount of current increases torque at higher speeds in order to produce any meaningful acceleration unless you shift the drop off of the torque curve to higher speeds.
