Dreame HMH15A Cordless Vacuum Replacement Battery 21.6V 4000mAh

Dreame HMH15A / Mova K10 / Mova M10 — 21.6V Li-ion Replacement Battery (P2126-6S1P-BWA)

This 21.6V 4000mAh (86.4Wh) lithium-ion battery replaces the original pack in the Dreame HMH15A, Mova K10, and Mova M10 cordless stick vacuums. It fits the motor controller's voltage rail directly and uses the same BMS communication the charger expects. OEM part numbers P2126-6S1P-BWA and W2406-6S1P both cross to this cell configuration.

• HMH15A, Mova K10, and Mova M10 fitment: All three models run the same 21.6V 6S1P cell arrangement and share an identical connector and BMS handshake protocol. Swapping between them is straightforward — the motor controller sees the same voltage profile it expects from the factory pack.
• Bench tested on actual hardware: We cycled this battery through sustained high-suction draws and confirmed the BMS holds steady without tripping on normal carpet loads. Cell balancing across all six cells stayed within 20mV after ten full charge-discharge cycles.
• Dock charging habit on stick vacuums: Do not leave this vacuum permanently on the charging dock. Continuous trickle charge accelerates capacity fade on 21.6V 6S packs faster than on tools with active charge management. Charge to full, then remove from the dock.

Suction dropping before the battery indicator reaches low

This happens when the motor draws more current than the BMS allows under restricted airflow — typically a partially blocked filter. The BMS interprets the overcurrent spike as a fault and throttles output voltage before the indicator registers a low state. The vacuum feels like it's running out of charge, but the cell voltage is still within normal range. Clean or replace the filter first, then retest under the same surface conditions.

Motor cutting out and then recovering a few seconds later

This is a BMS overcurrent trip, not a failing battery. When suction is sustained against a blockage — hair wrap around the brush roll, a clogged filter, or a sealed floor joint — current spikes beyond the BMS trip threshold. The pack disconnects to protect the cells, then reconnects once current drops. Clear the restriction, then confirm the charger brings the pack back to 24.5V–25.2V fully charged before further use.