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Can you use 2 ebike wheels front and rear or two rear ones on a three wheeler tricycle but operated by the one controller?

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    Interesting question, but its not about bicycles, its about electronic circuits. You might be better asking this on electronics.SE Consider that there's only so much power available, so you either use it twice as fast, or only send half as much to each motor.
    – Criggie
    Nov 22 '20 at 18:46
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    Yes your quite right in a way but it's about the circuitry on a ebike project I was thinking about doing.but thanks criggie.
    – Alan Walsh
    Nov 22 '20 at 22:40
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    Speaking as an electrical engineer, I would have doubts as to whether you could operate two wheels off of one controller if the controller was not designed for such duty. Nov 23 '20 at 0:35
  • Brushless motors (essentially all hub motors) would need a unique driver circuit each, as the electronic commutation must detect and react to the actual rotational position of the wheel (modulo pole count) Nov 24 '20 at 6:09
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I don't think that you can. Each wheel needs its own individual controller and throttle. That is the reason for you never see an e-bike rear wheel tricycle and instead they're always front wheel driven.

Also, if both powered rear wheels on a tricycle were operated by a single controller, you'd have steering problems.

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    I think you're wrong, because a little while ago I found a US manufacturer of e-bikes that produce a moto-style pedelec with both front hub and rear hub drive. I will see if i can find the link though I don't hold out much hope
    – JoeK
    Nov 23 '20 at 17:29
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    I think I must contradict: one of my neighbours having had a stroke and failing to maintain his equilibrium on a two-wheeler, rides an e-trike that has the motor-pedal-unit where the pedals normally are. But then I don't know whether it is a purpose-built machine from a specialised workshop.
    – Carel
    Nov 23 '20 at 18:51
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    @JoeK the question however was about using one control unit for two motors Nov 24 '20 at 6:07
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    @Carel a chain drive from the motor would make the the issue the same as when pedaling; you'd either need a differential, to only drive one rear wheel, or will suffer turning issues - even with pedal power. Nov 24 '20 at 6:07
  • @Chris Stratton, you are correct regarding the question wording but it could be interpreted as a single set of handlebar controls as the motor controller circuits are pretty cheap.
    – JoeK
    Nov 24 '20 at 8:11
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Theoretically you can if the motors are sensorless, and the speed controller as well, but in reality not, because most of the motor are sensored today, and also most of the controller can output a limited amount of current, and sure not enough to power even 2 low power motor. It might work with no load, but sure the controller will broke after you sit on the bike. There are out there some really powerfull controller, but the cost are not worth the risk. You can use one throttle with 2 controller, this is doable and done in the past, but you have to build yourself the split cable for both the controller. You also have to think about the battery, which might not be able to output current for 2 motor, to be safe you should use high quality cell, with 5/10C of discarge rate, or compensate with a lot of parallel batteries, which means 14Ah 36v batteries as bare minimum, better 48V 14Ah. This number are just said to be said, without any calculation since here we have many many variables.

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