Viomi Alpha 2 Pro 14.4V Replacement Battery 5200mAh

Viomi Alpha 2 Pro / VXVC15-JC / VXVC16-JC — 14.4V Li-ion Replacement Battery

This 14.4V 5200mAh (74.88Wh) Li-ion battery fits the Viomi Alpha 2 Pro, Alpha 2 Pro Plus, VXVC15-JC, and VXVC16-JC cordless stick vacuums. It replaces the original pack when capacity has dropped enough to cut cleaning sessions short. Voltage and BMS communication match the factory specification for these models.

• Alpha 2 Pro and VXVC-series compatibility: The VXVC15-JC and VXVC16-JC share the same 14.4V battery rail and connector housing as the Alpha 2 Pro line. The BMS in each of these models expects the same handshake protocol, so one cell format covers the full group without adapter modifications.
• Bench tested on actual hardware: We ran this pack through full charge and discharge cycles on the Alpha 2 Pro motor platform. The BMS held steady through both carpet-load current spikes and the lower draw of hard floor passes — no false overcurrent trips recorded.
• Dock charging behaviour on this vacuum: Remove the Viomi from the charging dock as soon as the indicator shows full. These vacuums draw a slow trickle indefinitely while seated on the dock — that continuous low-level charge accelerates cell degradation faster than regular charge-and-remove cycles.

Suction dropping before the battery indicator reaches low

This happens when the motor is fighting a restriction — usually a partially blocked filter or a compressed dust cup — and pulling more current than rated. The BMS responds by reducing output voltage to protect the cells, which the vacuum translates directly into weaker suction. The indicator reads the state of charge, not the motor load, so it can still show mid-range while suction is already degraded. Clean the filter and check the dust cup seal first; if suction recovers immediately, the battery is not the issue.

Motor cutting out mid-clean and then restarting after a few seconds

This is a BMS overcurrent trip, not a dead battery. When suction is sustained against a blockage or a clogged filter, current draw spikes beyond the BMS trip threshold and the pack shuts output temporarily to protect the cells. The few-second pause is the BMS resetting once current demand drops. Clear any blockage, clean the HEPA filter under running water, and let it dry fully before reinstalling — a wet filter restricts airflow just as badly as a dirty one. If trips continue with a clean filter on open-air suction, check the replacement pack is sitting fully locked into the battery bay.