Roborock A20 Air 21.6V Replacement Battery BRR-07-6S1P-2500F

Roborock A20 Air / A20 Flexi Lite — 21.6V Li-ion Replacement Battery (BRR-07-6S1P-2500F)

This is a 21.6V, 2500mAh (54Wh) lithium-ion battery for the Roborock A20 Air and A20 Flexi Lite robotic vacuum cleaners. It replaces OEM part numbers BRR-07-6S1P-2500F, BRR-07-6S1P-2500S, and BRR-07-6S1P-2500L. The battery powers the motor and onboard electronics through the full cleaning cycle.

• A20 Air and A20 Flexi Lite compatibility: Both models run the same 21.6V six-cell series pack with a shared connector layout and BMS communication protocol. One battery covers both platforms — voltage rail and cell count are identical across the A20 range.
• Bench tested on actual hardware: We cycled this pack through full charge and discharge runs on the A20 platform. The BMS handshake completed correctly, overcurrent protection tripped at the expected threshold, and cell balancing held within spec across multiple cycles.
• Dock charging habit for the A20 Air: The A20 Air is frequently left on its dock between uses. Continuous trickle charging accelerates capacity fade in lithium cells. Charge the battery to full, then remove it from the dock — only return it to charge when depleted.

Suction dropping before the battery indicator reaches low

This happens when the motor draws more current than the BMS allows under load — typically caused by a partially blocked filter or brush roll restriction. The pack voltage sags under peak draw, and the BMS interprets this as low-cell condition before the state-of-charge indicator reflects it. The vacuum appears to lose power early, but the issue is motor load, not actual battery capacity. Clean the filter and clear the brush roll, then check whether the indicator and suction loss now align.

Motor cuts out briefly then restarts mid-clean

This is a BMS overcurrent trip, not a dead battery. When suction is restricted — blocked filter, tangled brush, or a sealed nozzle — the motor draws sustained current above the BMS threshold and the pack cuts out to protect the cells. Once current drops, the BMS resets and the motor restarts. The fix is not a new battery. Clear the restriction, check that the filter is seated correctly, and the cutout cycle will stop.