Xiaomi Mijia 1S Replacement Battery 14.4V 5200mAh

Xiaomi Mijia 1S — 14.4V Li-ion Replacement Battery (BRR-1P4S-2600S)

This 14.4V 5200mAh Li-ion battery replaces the original pack in the Xiaomi Mijia 1S cordless handheld vacuum cleaner. It also fits the Mi Robot Vacuum-Mop, Roborock S6, Roborock S50, and over 15 additional models sharing the same voltage rail and connector. Capacity figures are drawn from the product data — 74.88Wh total energy.

• Shared platform across Mijia and Roborock vacuums: These models use the same 14.4V cell architecture, BMS handshake protocol, and connector pinout. Swapping the pack across compatible units works without modification because the charger negotiates with the BMS, not the chassis.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on the Mijia 1S motor platform. The BMS held cutoff correctly at low-cell threshold and did not trip on normal suction load cycles across hard floor and carpet transitions.
• Dock charging habit on Mijia cordless vacuums: Do not leave the vacuum sitting on the charging dock continuously between uses. The Mijia 1S dock delivers a trickle current once full, and sustained trickle exposure accelerates capacity fade in this cell format. Charge to full, then pull it off the dock.

Suction dropping before the battery indicator reaches low

The Mijia 1S motor draws harder when airflow is restricted — a partially blocked filter forces the motor to pull more current to maintain suction. That higher draw causes voltage to sag at the cell level earlier in the discharge curve. The BMS reads the sagging cell voltage and throttles power before the indicator LED registers a low state. Clean or replace the HEPA filter first — if suction recovers and lasts longer, the battery is not the cause.

Motor cuts out mid-clean then recovers after a short pause

This is a BMS overcurrent trip, not a dead cell. When sustained suction against a blockage or dense carpet pushes current past the pack's trip threshold, the BMS disconnects the output to protect the cells. The cutout feels abrupt — suction stops, then returns after 10–20 seconds once the BMS resets. Clear any blockage at the nozzle or hose, then check that the filter is not choked. If the trips continue on an unobstructed vacuum, verify cell voltage at the pack terminals — a degraded cell sitting below 3.2V under load will trigger this cutoff repeatedly.