Vex iq Smart Motor Breaking

Vex IQ smart motor breaking


Our VEX Iq SMART MOTORS are not functioning after a few hours of use. After some time, motors powering the drivetrain would randomly either not function at all or spin with 30% of it’s original power. After this, everytime the motor is supposed to spin, it 2/3 of the time completely stays immobile and the other 1/3 of the time it slows to a crawl. This has happened to 5 motors already and we are wondering if something is wrong.


We are using a gen 2 brain
We are pretty sure that everything is updated to the latest version except the smart radio.
We have 2 motors, one peering each side of the drivetrain

Attempted solutions

The only fix right now is replacing motors.

We have tried:

  • replacing wires that lead from brain to motor
  • changing ports on the brain
  • switching motors
    None of these have worked.

Please tell us if you have solutions! At this rate, we will burn through all our motors in the next few months!

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Sounds like they are getting overheated, which happen with prolonged use. Check them once not working for high temp (more hot than usual to touch). If so, best to let them cool down and wait to use them until fully cool down. Compressed air may work too cool outside but I don’t know how effective internal cooling will be.

If motors don’t work after cool down period, and have not returned to original quality/power, contact VEX for replacements.

Thank you for your answer! Just to clarify, overheating can be a problem for all vex motors including smart motors, right?

Yes, while mostly talk about for V5, any motor put under load for enough time will begin to overheat.

Hi @former47c! Silly question but after your “few hours of use,” what is the battery level when the “malfunction” occurs? When the battery level gets low, it exhibits some of the same symptoms you are experiencing like the slowdowns and stoppings. At lower battery levels ( < half full), the power given is potentially not sufficient enough to run the motors how they normally would.


Do the motors work later?

What is the great ratio on the drive base, and how big is the robot?

I don’t think this isn’t as much of a problem with the gen 2 batteries.

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This might be the issue! at the time it broke down, the battery was at 40%. We are charging the battery to 100% to test this. Thanks!

This might be the case, we are using I think somewhere near a 5:3 gear ratio. with one motor powering each side of the drivetrain (2 wheels).