motorbikemike45
Member
Late last Summer I finished my second e-bike using a Ping 48V, 15aHour battery and an e-bikekits.com direct drive rear wheel hub motor with a 7 speed cassett. The bike has great speed and power with a 25 miles per charge range running WOT. The e-bike kit comes with a 3 speed switch that cuts down the voltage the controller puts to the motor (24, 36, and 48), which is great for going slower on bike paths, in busy foot traffic on multi use trails, etc. In a little experiment to increase range last Fall I cut speed to the lowest setting on the switch and ran till the battery pooped out. It extended the range only 3 miles, from 25 to 28 miles on the same flat path I usually travel, though it took me about an hour longer to reach the range limit. This path allows for very few stops, so accelerating the bike from a stop is not a significant factor.
I know that it takes a bit more work to push a bike and rider faster through the air due to increased air resistance, but the bike and rider take about the same amount of work to move the weight and overcome friction loads a given distance at a given speed. I understand that Watts are a measure of work, so I'm asking if going slower on an e-bike will make much difference in the range. A gasoline engined motored bike can get much better or worse mileage depending on how much throttle is used, but it doesn't seem to make a whole lot of difference on an electric vehicle at a relatively constant speed. In other words, for a given load over a given distance will the Watts required be the same at 24V, 36V, and 48V at WOT in each voltage? Will the amps increase at different voltages to move a fixed weight a fixed difference and use the same Watts. Volts X Amps = Watts
I know that it takes a bit more work to push a bike and rider faster through the air due to increased air resistance, but the bike and rider take about the same amount of work to move the weight and overcome friction loads a given distance at a given speed. I understand that Watts are a measure of work, so I'm asking if going slower on an e-bike will make much difference in the range. A gasoline engined motored bike can get much better or worse mileage depending on how much throttle is used, but it doesn't seem to make a whole lot of difference on an electric vehicle at a relatively constant speed. In other words, for a given load over a given distance will the Watts required be the same at 24V, 36V, and 48V at WOT in each voltage? Will the amps increase at different voltages to move a fixed weight a fixed difference and use the same Watts. Volts X Amps = Watts
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