Running two 24v motors off one battery

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Sep 21, 2017
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Hello,
I hope that this isn't a daft question. I want to build a ride on car for children that goes over rough ground as well as on the level. If I use two 24v motors (one for each back wheel) should I run these off a 24v battery or a 48v battery, I am assuming the first one. Also if I am linking these motors to a controller and electric foot pedal can both motors be run through one controller? Should this controller be a 24v one?
Thanks James
 
Two motors with each their own controller and one battery.
I dont know if that can be done or not, but I'd guess that it could be done.
Make sure the battery itself can handle the controllers output, so 24V 10A for each controller, then be sure to have 24V and 25A battery discharge capability. Then you'd maybe have to put in some diodes on each controllers pos (or negative) wire.

If, however you plan to run two motors off of one controller, it cant be done as far as I am aware. This question does come up but I doubt it could be done because each motor needs current at exact times and thats too hard to do with two motors spinning fast.
 
Some of the above info can be misleading. From actual experience with two wheel pusher trailers you can definitely run two motors from two controllers with one throttle and one battery pack. There will be no need for a differential, etc. as the "independent" motors will let either one speed up or slow down as needed for smooth cornering without "fighting" each other. Needless to say, the motors and controllers need to be a "matched" set.

Statements above concerning adequate battery, etc. to feed both controllers is important.

There is a thread on here somewhere where a tadpole trike was set up with two motors and two controllers and one throttle. It worked great with no cornering issues. Whenever this subject comes up there is concern expressed about needing either a mechanical or electronic "differential", but I believe that issue has been put to rest. On the other hand, a two wheel drive bicycle with different motors and/or different wheel sizes needs to have some sort of electronic interface so the two motors don't fight each other. When I experimented with this type of setup, I just used two throttles and determined which one had to be the master and which the slave when using both during a steep climb.

Good luck with your project. :D
 
ProgramThyself said:
How will motor startup / position sensing work if there are two motors with one controller? I don't think you can just wire them in series or parallel.
You can if they're brushed.

Series two identical brushed motors and each gets about half the voltage (so half the speed), but full current (so full torque).

Parallel two identical brushed motors and each gets about half the current (so half the torque), but full voltage (so full speed).


So, if you needed to get all the torque *and* all the speed, *and* use them on one controller, you'd have to use a battery of twice the voltage (and a controller rated for that), if seriesing them.

If paralleling htem, you use a battery of the rated voltage, but a controller (and battery) that can output twice the amps.

In practical consideration, you end up with effectively an electronic differential; power works itself out between the motors based on their speed in a turn.

If you found too much of a problem in turns you'd need separate controllers with a differential throttle setup (one throttle but fed thru an electronic "divider" that gives less voltage to the inside wheel and more to the outside wheel in a turn). I don't think you'll run into that in a low power system.





If they're brushless, then no, you can't run two off of one controller UNLESS their shafts (or rotors) are physically locked together at the same electrical angle/position, so that the position sensing from either one also works for the other. This essentially makes them one larger motor.

If they're on separate wheels with separate axles, then that can't be the case.
 
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