# Running different voltage motors from one battery

I would like to run a 12v motor and a 24v motor both from a 24v battery, through an Arduino. Is it possible to use a regulator for just the 12v motor to stop it being damaged, but still get the full 24v to the 24v motor?

Also, could the Arduino be powered from the same battery, I believe it operates at 5v, or does it need its own power supply?

• Please add more details about your motor power consumption, we can't guess if a regulator would be enough or not. Also, have a look at the Arduino board that you have, it will state its max operating voltage. Be careful, spikes generated by a motor could damage its internal regulator. – HatimB Feb 24 '17 at 14:38
• The 12v motor draws 1.4a and 8.5w, the 24v 0.7a and 24W. Is this all the information required? Please excuse my ignorance I am very inexperienced with electronics. – Sam B Feb 24 '17 at 14:41
• Sam, please add all the details in the question itself. Also, if possible dad datasheets and presently what you have for driving motors. Your question will definitely get good answers. – Umar Mar 3 '17 at 3:46

This is odd $12V*1.4A>8.5W$ you provided in your description. Considering the lack of more info and to stay on the safe side, I'm going to use the max figures.

First, do these calculations:

Power dissipated in the regulator $P_{REG}=(24V-12V)*1.4A$

The regulator's internal temperature. $T_{j}=T_{AMB}+P_{REG}*(R_{th-jc}+R_{th-hs)}$

Where:

$R_{th-hs}$ is the heatsink's thermal resistance.

$R_{th-jc}$ is the regulator's junction to case thermal resistance.

$T_{AMB}$ is your the ambient temperature. The max expected temperature.

If $T_{j}>T_{j-MAX}$ which you can find on the component's datasheet, then look for another one until you find the one that suits you. Make sure to add some margins in case your input voltage gets too high for example. Follow the manufacturer's recommended schematic to make it operate correctly.

Side note: Connect the regulator to the heatsink using a thermal paste otherwise, you would have to consider an additional thermal resistance which is not good :)

• The motor is from this link aliexpress.com/item/… The motor I am choosing is the 12v rated one, with a no load speed of 255rpm, which Is where I got the power and current numbers from. Does this mean that the actual voltage it uses to rotate at 170rpm (the rpm quoted for max efficiency, and my desired rpm) is less than 12v? – Sam B Feb 24 '17 at 17:48
• The voltage range of all motors is 6-30V. I think that you don't really need a 12V supply, maybe clamp the overvoltages over 30V but it should work with a 24V supply. Except if there are other conditions that you should comply with when using the motor out of its rated voltage. I do not like specifications that are usually provided in these kind of websites... – HatimB Feb 27 '17 at 10:28