I have a dc motor which needs more than 10V to run efficiently, so instead of running it on electric cells, I usually run it using my laptop's power. I connect a USB cable to my laptop and the other end of the cable to the motor(red and black wire of the cable is connected to the motor).

Now my worry is weather doing this is going to create any negative effect on my laptop or it's battery?

  • I think there would be big difference between motors and any other electric consumer, so answers to this question are applicable also for you: superuser.com/questions/690074/…. Even your laptop has 12V batteries usb output is always 5V! – Máté Juhász May 16 '15 at 10:32

The answer is: It depends. If your motor is drawing considerably more than 500 mA at 5 V, you might damage your USB voltage regulators. Do not attempt to connect USB ports in series to get 10 V. Doing so will short-circuit the USB port.

Of course, it’s yet another question whether the motor actually does what it’s supposed to do if provided with only 5 V.


This will not impact your laptop though obviously you are draining the battery slightly faster if not on mains.

Over time, the motor may suffer slightly as it will be running at 5v instead of 10v & running motors below rated voltage can cause heating issues. But I really doubt this is going to have any noticeable impact in this case, that really applies to high power motors.

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