# multi motor controllers



## frodus (Apr 12, 2008)

Car? Truck? Motorcycle?

The likelyhood that you'll find a controller that will drive multiple brushless hubmotors is next to zero. One controller per motor in most cases with brushless hubmotors. 

If its a motorcycle, the Enertrac hubmotor is a good start.


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## Hollie Maea (Dec 9, 2009)

Why do you want hub motors? Hub motors are something that for whatever reason really tickles people's fancy, but they have some serious disadvantages. For one thing, they have to be somewhat exotic, as they must produce power at much lower RPMs, since there is no gear reduction. There are some small ones that work in scooters, but not a lot of good car sized options (since you want 30hp continuous, I'm going to assume you are putting this in a car). A bigger issue is that hub motors are unsprung mass, and there are some significant mechanical issues to overcome. As far as I know, there still aren't any OEMs that have successfully implemented a hub motor drivetrain.

Now, the idea of a smaller motor on each wheel is a worthy prospect, but a much better way to implement that is with a gear reduction and half shafts. The biggest hurdle in the DIY community for this scheme is the gear reductions. There are some you could get, but they won't be cheap (what is your budget, anyway?) But, with money, it is certainly doable.

But you can forget about using a single controller. Series wound brushed DC motors can have multiple motors driven by a single controller, but only if they are all on the same shaft. In this case, you will NOT want each motor to always have the same torque command, unless you are trying to build a drift car or something. So you'll need multiple controllers. No problem there--just like there are small motors available, there are also small controllers available. You will also need a "controller of controllers" to send the correct torque commands to the wheels. That will be a signal level device, so the hardware won't be expensive, but the software could be somewhat challenging. But it has been done, and with a good budget you could just buy the whole system.

But anyway, you shouldn't use series wound DC regardless. You definitely need regen. With a normal setup, regen slightly increases range, which may or may not be worth it (plenty of arguments on this board). But regen also gives you the ability to control torque in both the positive and negative directions. And with a four wheel setup, that's pretty important.


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