Dreame H12 Cordless Vacuum Replacement Battery 21.6V 3700mAh

Dreame H12 / H12 Pro Series — 21.6V Li-ion Replacement Battery (W2210)

This is a 21.6V, 3700mAh lithium-ion battery for the Dreame H12, H12 Pro, and H12 Pro Plus cordless vacuum cleaners. It fits the OEM part number W2210 and W2210-6S1P-BWB battery positions. When the original cell loses capacity and suction drops off well before the indicator hits low, this is the direct replacement.

• H12 and H13 Pro platform compatibility: These models share the same 21.6V six-cell architecture and identical battery housing connector. The BMS handshake protocol across this range is consistent, so one replacement cell covers the full listed model group without modification.
• Bench tested on actual hardware: We ran this cell through charge cycles on the H12 platform and confirmed the BMS communicates correctly with the vacuum's motor controller — charge acceptance, discharge cutoff, and cell balancing all behaved within the OEM specification range.
• Dock charging habit on the H12: Do not leave the H12 sitting on the charging dock after it reaches full charge. Continuous dock contact applies a low-level trickle that accelerates capacity fade in lithium cells. Charge to full, then remove the vacuum from the dock.

Suction dropping before the battery indicator reaches low on the H12

This happens when the motor draws more current than the BMS expects — usually caused by a partially blocked filter, not a failing battery. A restricted filter forces the motor to work harder, pulling sustained high current that triggers a voltage sag well above the BMS's low-cell cutoff threshold. The BMS reads the sag as a near-depleted pack and throttles power to protect the cells. Clean or replace the filter first, then retest — if suction holds steady through a full clean floor cycle, the battery is not the root cause.

Motor cuts out mid-clean then recovers after a few seconds

This is a BMS overcurrent trip, not a dead battery. When suction is sustained against a blockage or a heavily loaded carpet, current draw spikes past the BMS's overcurrent threshold and the pack disconnects to protect the cells. The BMS resets automatically once current demand drops — which is why the vacuum restarts after a brief pause. Clear any blockage, check that the filter airflow is unrestricted, and confirm the voltage reads at or above 21.6V on a full charge before suspecting a cell fault.