Xiaomi B105CN Cordless Vacuum Replacement Battery 14.4V 5200mAh

Xiaomi B105CN / OMNI 1S Cordless Vacuum — 14.4V Li-ion Replacement Battery (BRR-2P4S-5200S)

This 14.4V 5200mAh Li-ion battery replaces the original pack in the Xiaomi Mi Vacuum Cleaner B105CN, OMNI 1S, B101CN, and compatible models sharing the BRR-2P4S-5200S specification. It fits the cordless handheld/stick form factor and restores full suction power to the motor drive circuit. Capacity is rated at 74.88Wh.

• B105CN / OMNI 1S platform fitment: These models share a common 4S2P cell configuration and the same BMS handshake protocol with the Xiaomi charging circuit. The connector pinout and voltage rail are identical across the listed variants, which is why one pack covers the full range.
• Bench tested on actual hardware: We cycled this pack through the Xiaomi motor controller at full suction load. The BMS held the 14.4V nominal rail without tripping on sustained draw, and cell balancing across the 4S arrangement stayed within 20mV across a full discharge cycle.
• Dock charging behaviour on this vacuum: Do not leave the vacuum sitting on the charging dock continuously. The Xiaomi dock does not cut trickle current reliably once the pack is full. Remove the vacuum from the dock when the charge indicator shows complete — leaving it docked between every use accelerates capacity fade on this cell chemistry.

Cordless vacuum losing suction before the battery indicator reaches low

This happens when the motor draws more current than the BMS expects — usually caused by a partially blocked filter or bin, not a failing battery. A restricted airpath forces the motor to work harder, pulling current above the BMS overcurrent threshold at a pack voltage that still reads mid-range. The BMS reads a voltage sag under that elevated load and throttles output early. Clean the filter and empty the bin first, then retest. If suction holds at full power longer, the battery was fine — the airpath restriction was the cause.

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

This is a BMS overcurrent trip, not a dead battery. When sustained suction against a blockage — carpet pile, a lodged debris piece, or a clogged cyclone — pushes instantaneous draw past the BMS threshold, the pack disconnects the output rail to protect the cells. The BMS resets itself after a few seconds once current demand drops. Clear any blockage, check that the cyclone and filter are unobstructed, and restart. If the cutout repeats on an unobstructed vacuum, measure pack voltage at rest — it should read at or above 16.0V on a full charge.