Specifically, on kick scooters. Is it correct to think that when climbing a steep hill, lowering the powerlevel/maximumspeed, while kicking to maintain that speed is the best way to keep the motor cool as possible? Also would that maximize range? Seems like my I-Max T3 scooter (350W hub motor; 36 volt 10ah battery) exceeded the maximum range by at least 5 miles by kicking up steep hills in lowest power levels and then descending in top speed mode. I'm confused about this because I've heard people talk about doing the reverse on electric bicycles. That is, powering up steep hills in sport mode and then decreasing to a lower power level when reaching the top. Perhaps that is how to minimize strain on the human rather than the motor?
What is the relationship between powerlevel and strain on hub motor when hill climbing?
- Thread starter DBentz
- Start date
Totally! Love the superman feeling of physical effort magnified by the quiet, invisible hand of electricity! But do you know the effect on temperature of the motor at different human/battery power input proportions? In other words, does using a lower number setting on the throttle controller of a direct drive hub motor at lower road speeds, have any effect on motor temperature? Is it just as easy or hard on the motor to keep the throttle at the highest speed setting while never exceeding the maximum allowed by the lowest number? I would think that using the lower number would reduce the amount of electricity going to the motor so that it would have less energy coming into it and therefore not get as hot. But maybe if you never exceed the maximum speed of the lower setting, just as much power flows into the motor at #1 setting as at #5. Like an either all on, or all off, switch, rather than varying the amount of electricity supplied while in the on position.
I don't know much about this, but here are a couple of thoughts. Helping a motor by kicking or pedaling will reduce strain on the motor and battery, resulting in better range and less heat. It should take the same amount of power to maintain a given speed, no matter what your max speed setting is, unless I'm misunderstanding how your system works. Going slower means less wind resistance, but motors, especially direct drive I think, are often less efficient at lower RPM, and might create more heat struggling uphill at low speeds.
John Benford
New Member
John Benford
New Member
I’ve been wondering about his too. If the motor is on the low end of efficiency (as it is when under speed for the setting) during a hill climb, it seems to me that the difference between PAS settings makes little difference. Normally a higher PAS setting raises the voltage, therefor the power, but if you’re running less than, say, 10% efficiency due to low speed, increasing the PAS setting will make little noticeable difference. I’ve also wondered if pedaling really hard to keep from stalling/stopping completely is worth the effort. If you’re running at poor efficiency speed, really hard pedaling beyond what the motor can do at the given speed, is providing more power, but it may not be translating to speed. If the motor is already approaching stall speed you might be losing the heat battle anyway and wasting your own energy. Easier pedaling might still get you up the hill just as fast, as the hard pedaling isn’t translating to speed, but instead met with magnetic resistance. This theory would take some testing. I’ve gone up the same steep hill (>13% grade) twice, once pedaling so hard I felt like dying, the next time pedaling much easier. There was no noticeable difference in speed getting up the hill at the same PAS setting.
JRA
Well-Known Member
I have come to the same conclusion as John, spinning a higher cadence in a complimentary gear ratio to the output of the motor relative to the grade (most effective at 350w +/- I have found) while hill climbing with a hub motor will keep the motor temp in control. Grinding up hill in a big gear lugging the motor will only result in both you and the motor overheating.
Kicking there would be similar to increasing pedaling cadence.
Q1: Kind of. Lowering PAS means lowering max output of the motor. So - yes, it will run cooler, and - no, this isn't necessarily the best way to maintain speed because when you lower the PAS, you have to compensate this with more sweat, so at some point you can't kick any harder to maintain the speed - while motor could've added something if you had increased PAS level.
Q2: Any increase in sweat to amps ratio will increase the range. Shut the motor off completely and you'll never run out of battery charge.
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