About this replacement
Roborock A30 Pro Series — 21.6V Li-ion Replacement Battery (BCR-61P-4000MS)
This is a 21.6V, 4000mAh (86.4Wh) Li-ion replacement battery for the Roborock A30 Pro and A30 Pro Combo robotic vacuum. It slots into the same battery bay and connects to the same BMS interface as the original cell. When the factory battery degrades and suction performance drops noticeably, this unit restores the vacuum to full operating voltage.
- A30 Pro and A30 Pro Combo fit: Both models run the same 21.6V power rail, use the same BCR-61P-4000MS connector format, and rely on the same BMS handshake with the dock charger. One battery covers both configurations without modification.
- Bench tested on actual hardware: We cycled this battery through full charge and discharge on the A30 Pro platform. The BMS registered correctly with the dock, accepted the charge sequence without fault codes, and held voltage at load across the motor and brush-roll draw.
- Dock charging on the A30 Pro: Do not leave the A30 Pro sitting on its dock continuously between uses. Robotic vacuums on permanent dock charge accumulate trickle-charge cycles that accelerate capacity loss. Charge to full, then remove from the dock until the next scheduled clean.
Suction dropping before the battery indicator reaches low on the A30 Pro
The A30 Pro's BMS monitors cell voltage under load, not just at rest. When the battery has aged, internal resistance rises and voltage sags sharply the moment the motor ramps up — especially on carpet or when the brush roll is partially blocked. The vacuum's suction controller reads that sag as a low-power condition and throttles the motor before the indicator LED reflects it. Replacing a degraded cell with a fresh 4000mAh unit at full 21.6V removes that voltage sag and restores consistent motor output across the full cleaning cycle.
Motor cuts out mid-clean then recovers after a few seconds
This is a BMS overcurrent trip, not a motor fault. When airflow is restricted — blocked filter, clogged brush roll, or heavy debris — the motor draws above its rated current to maintain suction, and the BMS cuts power to protect the cells. The brief recovery happens once the BMS resets and current drops back within threshold. Clean the filter and clear the brush roll first; if the cutout persists on a clear path, the existing battery's degraded cells are hitting the BMS current limit at normal draw. Check cell voltage after a full charge — a healthy pack should read at or above 24.0V open-circuit before load.