Is it a good idea to connect two DC motors on a single driver channel? Here are the motor specs:

Operating Range: 6 - 12VDC · No load current: 40mA (6VDC) · No load current: 70mA (12VDC) · Stall current: 360mA (6VDC) · Stall current: 1600mA (12VDC)

The driver chip is DRV8838 with the following specs:

H-bridge motor driver: can drive one DC motor Motor supply voltage: 0 V to 11 V Logic supply voltage: 1.8 V to 7 V Output current: up to 1.7 A continuous (1.8 A peak); operation at low motor and logic supply voltages reduces the maximum continuous output current

What can go wrong? Thank you!


At 6V, it should be fine. At 11V (the driver max) the stall current of both motors combined will exceed the driver max current, so they may not start reliably, but once started, should run OK if you don't stall the motors.

Don't expect both motors to run at exactly the same speed, though.

  • \$\begingroup\$ Why won't the motors run at the same speed? P.S. I'm trying to use two DRV8838 drivers to drive 4 motors on a RC car. One driver for the left side and the other for the right side. \$\endgroup\$ – user3070256 Dec 12 '14 at 13:14
  • \$\begingroup\$ They will be close, but any difference in friction or mechanical load can result in a speed difference. If one motor was left and the other right, the car wouldn't steer straight. Putting both L motors on one driver and R on another should be OK (except maybe on patches of ice!) \$\endgroup\$ – Brian Drummond Dec 12 '14 at 13:53
  • \$\begingroup\$ DC brushed hobby motors rarely run at the same speed, given the same supply voltage and load. They will be close but they won't be exact. There a lot of factors but a couple of them are: exact brush position & magnet strength is usually never identical between similar motors. \$\endgroup\$ – Dwayne Reid Feb 10 '15 at 20:23

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