why does my robot brown out mid match
Most Likely Cause: Loose or Damaged Power Connections
A physical disruption in your power path is the easiest and cheapest issue to check. According to FTC Docs, a loose or disconnected power wire to the REV Control Hub is a primary reason for unexpected mid-match disconnects. You should check the tightness of your XT30 power connectors, as their male pins compress over time and lose their snug fit. To confirm or rule this out, perform a physical inspection: check if the connectors fit tightly together with a slight amount of retention when pulled, and gently jiggle the power cables to see if the robot's power momentarily cuts out. If the connection is loose, you may need to replace the cable, repair the hub connector, or use an adapter cable to transition to more robust connectors like Anderson Powerpoles .
Second Most Likely Cause: High Current Draw and Actuator Overload
Excessive current draw from your motors and servos temporarily drops the system voltage, which can cause a brown-out that disrupts the Robot Controller's Wi-Fi antenna. Game Manual 0 states that FTC motors can draw up to 11 amps each when stalled, whereas the battery is likely to blow its fuse at 20 amps. Even before the fuse blows, drawing too much current causes low voltage and sluggishness. You should check if your robot is stalling more than two motors simultaneously, using more than four motors on a traction drivetrain, or utilizing very low gear ratios (such as configurations close to 1:1). Additionally, FTC Docs notes that low-torque configurations or high-friction systems force motors to draw significantly more current to move the same load, causing the battery voltage to "sag." You should also check if you are using high-transient actuators, such as certain super-speed servos, which can pull brief but massive spikes of current when they start moving or encounter sudden loads .
Third Most Likely Cause: Battery Degradation and Overheating
If your wiring is secure and your current draw is reasonable, the battery itself may be failing to sustain the required voltage under load. FTC Docs explains that as NiMH batteries age, individual cells can degrade or fail at different rates, especially if subjected to physical drops, deep discharging, or overcharging. A battery with failed cells cannot provide its peak power output and will suffer from severe voltage sag. Furthermore, using a battery that is still hot from charging increases its internal resistance, which reduces its power output. To diagnose this, check the physical temperature of the battery before the match and test its health using a battery tester. For further troubleshooting, you can refer to the REV Robotics 12V Battery Best Practices and Troubleshooting guide (https://docs.revrobotics.com/duo-control/troubleshooting-the-control-system/12v-battery-best-practices-and-troubleshooting) .