Connecting two motors in series

[fabieville]

If I connect two motors in series would it allow me to use a higher voltage to power the motors without causing any damaging effect like overheating?
Say for example I have (2) 24v 350watt unite my1016z gear reduction motors connected in series. Would it be safe to power the connection from either 48v or 36v instead of the 24v?
What effect would I have now seeing that they are connected in series instead of parallel?
Would it be more speed, torque, same speed like at 24v, reduce speed, overheating etc.?

My main goal is to achieve more speed or torque or both without causing the motors to run hotter than they would normally ran at 24v.

 

[Drunkskunk]

If the motors are brushed, then you can connect them in series with few problems. They will divide the voltage in half, so if you run 48 volts from the controller, you will have 24 volts at each motor.

Both motors should be running the same wheel. if you're driving 2 different wheels, you may need 2 controllers, as a condition where one wheel gets stuck while the other spins free could cause enough imbalance to fry one of the motors.

 

[dogman dan]

If brushless, 2 controllers one for each motor. Two motors can provide the same power, but with less heating of each motor. If you double the power, each motor still might heat the same as one did before.

A 24v motor run on the same wattage but more voltage should not heat much more. So 24v 20 amps, would be similar to 48v 10 amps. But you'd get a higher top speed possible with 48v. Bottom line, the wattage the motor is being asked to handle is the same. Think in watts or watt hours to compare things that run at different voltages.

That's just a math example, I'd say try running just one motor on a 36v controller, up to about 600w(15 amps controller) and see how it does. Then if you want more watts without heating up the motors add the second motor also running at 15 amps.

Then you'd have 36v speed, but 1200w of power for hills etc.

It is though, just a hell of a lot simpler to just put a 1000w motor on the bike, like a mac 10t, Ezee, or something similar. One that can run on 48v with no problems.

 

[fabieville]

If for example I use a 48v 30ah lifepo4 battery to power (2) 24v 350watt motors connected in series would each motor see half of the 48v which would be 24v and would the amp double to 60amp seeing that the motors would be running off 24v or I would still just have 30amp the max?

 

[d8veh]

The current depends on the controller. If it's a 30A controller, both motors will get 30 amps.

 

[jmac]

It appears that the motor is brushed, although nearly every site I found for it didn't mention that fact. (But, brushless is a selling point so most salespeople would list if if that was an option).

So, yes, you can run your 24v brushed motor in series on 48v.

But no, you can not also double the amperage to 60A because both motors would see 60A.

In series you split the voltage, in parallel you split the amperage. You can't do both unless you have 4 motors.

If you provide more information on what you want to do with the motors, and why, we can probably give you something more than just a yes or no answer. We might be able to suggest a solution you haven't thought of yet.

 

[fabieville]

In regards to this question that I asked:
"If for example I use a 48v 30ah lifepo4 battery to power (2) 24v 350watt motors connected in series would each motor see half of the 48v which would be 24v and would the amp double to 60amp seeing that the motors would be running off 24v or I would still just have 30amp the max?"

What I meant was that when you connect the motors in series they would both use half of the 48v which would be each motor using 24v so what happens to the 48v, is it shared between the motors or does half of it burn off as heat?

Also if each motors receive 24v at 30ah from the controller that means each motor is allow to pulled 720watt so the total power from both would be 1440 watt which would equal back to the original 48v 30ah rite?

 

[dogman dan]

Each motor would see half the amps, of 48v, I think. Voltage same, but the amps would be divided between the motors.

Would the first motor in line take more of the wattage than the second? I don't know. What I mean is, would voltage sag as it passed through the first motor? Would it be more like motor one has 48v, and motor 2 a lot less?

I'd want to run two brushed motors in parallel. split the power wires before the motors. Then each motor should run at the same voltage, and the wattage would be more or less equally shared.

Screw it, brushed controllers are so cheap. put the Y connector before the controller, and run two controllers.

 

[jmac]

I'm inclined to also suggest that 2 controllers is a better way to go, but still would prefer to know what you are doing before I weigh in on that.

In series amperage is always the same. Amps are simply the number of electrons passing through, they can't stop in one spot but have to make an entire circuit. Think water in a pond waterfall system, the same amount of water is recirculated by the pump but you might have 2 waterfalls, adding the two together you get the total height. If the motors are identical you should see essentially equal voltage across both (and you can just use a multimeter on each side to see that, just like checking a battery cell in series).

I would personally not put motors in series without a very good reason, or even parallel on the same controller without a very good reason. You won't get equal performance out of the two motors in either circumstance and there are a lot of ways that could cause you issues unless the system is designed to take that into account.