About this replacement
MeiZu M8C / M810H — 3.85V Li-Polymer Replacement Battery (BA810)
This is a 3.85V, 3000mAh (11.55Wh) lithium-polymer cell that replaces the original BA810 battery in the MeiZu M8C and M810H smartphones. It powers the processor, display, cellular radio, and all onboard functions. Fit this cell when the original no longer holds a charge or the phone shuts off unexpectedly under load.
- M8C and M810H compatibility: Both models run the same 3.85V battery rail, share the BA810 connector pinout, and use the same BMS handshake protocol — one cell covers both without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the M8C platform, confirmed BMS communication, and verified the charge IC accepted the cell without triggering a fault state at full current.
- Fuel gauge recalibration on first use: Disable fast charging in settings for the first complete discharge-charge cycle after installation. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated coulomb counter.
Sudden shutdown at 20–30% on the replacement cell
This happens because the fuel gauge IC still uses the discharge curve from the old, degraded cell. The new cell's voltage drops faster than the IC expects under modem or screen load, so the system reads a false low-voltage condition and shuts down before the actual charge is depleted. Run one full discharge to 0% and a complete charge to 100% without interruption. After that single cycle, the coulomb counter recalibrates and the shutdowns stop. If they continue past two cycles, check that the battery connector is fully seated — a loose pin causes intermittent voltage sag under load.
USB fast charge not accepted after cell replacement
On the first cycle after fitting a new cell, the charge IC may not handshake with the phone's proprietary fast-charge protocol — it falls back to standard 5V charging instead. This is a BMS initialisation behaviour on a fresh cell, not a fault with the battery or charger. Let the phone complete one full charge at standard rate. On the second and subsequent cycles, the protocol handshake completes normally and fast charging resumes. If fast charging still does not engage after two full cycles, test with a known-good fast-charge cable, as cable resistance can also block protocol negotiation.