Give the logic its own clean supply, and add a capacitor near the motor driver.
What the message means
Motors pull a large current when they start. The battery voltage dips and the board browns out.
Fix it in this order
- Add a large capacitor across the motor driver supply pins.
- Use a separate regulator or buck converter for the board.
- Use thick, short wires for the motor power.
- Add small capacitors across the motor terminals.
- Ramp the motor speed on start.
- Use a battery that can supply the peak current.
Why it happens
When the motors start they draw a large current, the shared supply voltage dips, and the microcontroller restarts. The fix is to keep the logic and the motors from fighting over one supply.
Give the motors their own battery or regulator and join only the grounds, add a bulk capacitor of a few hundred microfarads near the driver, and add a short ramp so the motors do not start at full power.
If you see this, do this
| You see | Do this |
|---|---|
| Resets only at start | Voltage dip. |
| Resets when stalled | Stall current too high. |
Related
brownout reset, motor stall current.
Last reviewed: November 2026. These are the usual causes and the order that finds them fastest. Test on your own board; clones and cables differ.