Xiaomi Mi 10 Ultra Replacement Battery BM4V 7.74V 2100mAh

Xiaomi Mi 10 Ultra / M2007J1SC — 7.74V Li-Polymer Replacement Battery (BM4V)

This is a 7.74V, 2100mAh (16.25Wh) Li-Polymer battery for the Xiaomi Mi 10 Ultra (M2007J1SC). It replaces the original BM4V cell when the existing battery no longer holds a charge or causes unexpected shutdowns. The cell dimensions are 108.00 × 41.10 × 7.00mm — confirm these against your existing battery before fitting.

• Mi 10 Ultra BM4V compatibility: The Mi 10 Ultra uses a dual-cell Li-Polymer stack managed by a dedicated BMS. This replacement carries the same BM4V designation and matches the connector pinout, cell voltage nominal, and protection circuit the device expects during authentication.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Mi 10 Ultra platform. The BMS accepted the cell without error flags, charge termination occurred at the correct 8.72V cutoff, and low-voltage protection triggered at the expected floor.
• Fuel gauge recalibration after swap: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC build an accurate discharge curve against the new cell before high-current charging is applied to an uncalibrated pack.

Sudden shutdown at 20–30% on the replacement cell

This happens when the fuel gauge IC is still calibrated to the old cell's discharge curve. The new cell hits a voltage cliff under modem or display load that the IC interprets as empty — even though the state-of-charge readout shows 20–30%. The phone cuts power to protect the board, not because the cell is dead. One full discharge-to-cutoff and charge cycle resets the coulomb counter and eliminates the false cliff.

USB-PD fast charge not activating on the first cycle after replacement

After a cell swap, the charge IC sometimes defaults to standard 5V/2A input on the first cycle because the BMS has not yet completed its handshake with the Mi 10 Ultra's proprietary fast-charge protocol. This is a one-cycle limitation, not a fault. Let the phone complete a full slow charge to 100%, then reboot. Fast charge resumes normally from the second cycle onward once the BMS registers a valid cell state.