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E-Bike motor selection, would it work? Answered

Im thinking of building an ebike, but unfortanately im stuck at the motor selection.

I was just thinking, if you use 250W brushed motors for them, can this motor be used...
If yes , just how to use it for a chain drive E-Bike?

Any help will be greatly appreciated.

5 Replies

rickharrisBest Answer (author)2017-05-30

Your link is broken but this bike uses a 2.25Kw BLDC motor an RC in fact.


He is running it at a low voltage and so not using all the available power.

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robobot3112 (author)rickharris2017-05-31

This brushless motor is 5cm, and max 900W... My only concern is, can it work without any reduction, as i donot want to throw away 35-40$ on something that doesnt work.

Thanks for the answer... Much appreciated.

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rickharris (author)robobot31122017-05-31

Your link is broken.

If by reduction you mean a gear reduction then yes it will need reducing to drive the bike. The motor is likely to be doing 20,000 to 30,000 RPM you need to work out how fast you need the w wheel to go and devise a suitable gearing. Watch the video and the associated video showing the build to see how he did it.

In principle 900 watts is a lot - at say 24 volts (a 6 cell lipo) your going to be drawing around 40 amps. A 5000 mAhr battery isn't going to last long.

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rickharris (author)rickharris2017-05-31

For my liking an RC motor trades speed for torque so unless you can gear it down a lot your 900 watts isn't going to seem as powerful as you think.

BTW have a look at Hobbyking as their motor is less than your going to pay for a more powerful motor, on paper at least. Most of these RC ratings are not for continuous running and you may need to arrange or think about cooling of some kind.

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