About this replacement
iRobot Braava 320 / 321 — 7.2V Ni-MH Replacement Battery (GPRHC152M073)
This is a 7.2V 1500mAh Ni-MH battery for the iRobot Braava 320 and Braava 321 floor mopping robots. It replaces OEM part GPRHC152M073 and 4408927. The battery powers the drive motor, onboard navigation, and the wet and dry cleaning systems.
- Braava 320 and 321 platform fit: Both models share the same battery bay, connector pinout, and 7.2V supply rail. The Braava's NorthStar navigation module and motor controller both draw from this single cell pack, so voltage stability across the discharge curve matters more here than in simpler devices.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on a Braava 320 unit. The BMS accepted the pack without error flags, and the robot completed navigation sequences without mid-cycle voltage drops or reset events.
- Ni-MH storage tip for the Braava 320: Ni-MH cells left in the robot on a powered base between cleaning sessions develop voltage depression faster than cells stored partially discharged and off the charger. If the Braava sits unused for more than a week, remove the battery from the dock entirely.
Why the Braava 320 stops mid-clean even with charge showing on the indicator
The Braava's battery indicator reads state of charge from a voltage estimate, not a fuel gauge IC. An aged Ni-MH cell can sit at a nominal voltage under no load but sag sharply the moment the drive motor engages. When voltage drops below the motor controller's cutoff threshold — typically around 6.0V under load — the robot halts and returns to base even though the indicator still shows partial charge. This is a cell capacity problem, not a software fault. A fresh 1500mAh pack restores the voltage buffer the motor controller needs to complete a full room cycle.
Braava 320 not responding after battery sits unused for several months
Ni-MH cells self-discharge at roughly 1–2% per day at room temperature. A Braava left on a shelf without a maintenance charge will have a deeply depleted pack within weeks. At very low voltages the robot's charging circuit may not recognise the battery as valid and will refuse to charge it. Place the battery on a standalone Ni-MH charger capable of a recovery or trickle mode first — recover to at least 7.0V — then return it to the Braava dock for a full charge cycle.