Power draw on a full power motor

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IRTGU

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Joined Apr 22, 2005

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81 Posts

Discussion starter · #1 · Nov 4, 2024

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What is the maximum power draw (requirements) to run a typical full power motor ?
I don't care about the battery specifications that come on e-bikes, just interested in the motor.

 

Bigwheel

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Joined Jan 12, 2004

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2,601 Posts

#2 · Nov 4, 2024

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Maximum available electric motor power is determined by volts x amps = watts. Doesn't mean that is the output at all times as that is determined by a controller that regulates the amp draw according to rider/terrain demands. Think of it as similar to a car that advertises 350hp but doesn't use anywhere near that much to propel it at lower speeds but does at its highest ones.

 

minimusprime

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Joined May 26, 2009

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2,266 Posts

#3 · Nov 4, 2024

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It mostly depends on the systems in question. Many/most systems are 36v systems, so 42 fully charged, down to 28v when the batteries are mostly depleted. A few of the systems, are 48v systems (TQ), so those start at 52v fully charged and run down to like 32v.

From my experience building a few DIY ebikes, you can expect current ranging from 15-30amps. Most full power systems are drawing around 450-500w at peak. I have a 750w bafang setup on my commuter... that thing will draw some serious current once the battery voltage starts to drop... in the range of 25-28 amps.