Meilan BA711 M6 Replacement Battery 3.8V 3000mAh

Meilan M6 Series — 3.8V Li-Polymer Replacement Battery (BA711)

The BA711 is a 3000mAh Li-Polymer cell at 3.8V, replacing the original battery in the Meilan M6, M6 Dual SIM, M6 Dual SIM TD-LTE, and M711Q. It restores charge capacity in handsets where the original cell has degraded and can no longer hold voltage under normal screen and modem load. Capacity is rated at 11.4Wh.

• M6 variant coverage: The M6, M6 Dual SIM, M6 Dual SIM TD-LTE, and M711Q all share the same battery bay dimensions, connector pinout, and BMS handshake protocol — one cell fits the full lineup without modification.
• Bench tested on actual hardware: We ran the BA711 through charge and discharge cycles on the M6 platform. The BMS accepted the charge IC handshake cleanly and held the protection threshold at the expected cutoff voltage under sustained screen-on load.
• Fuel gauge recalibration on first use: Disable fast charging 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 state — skipping this step causes erratic percentage readings in the first few days.

Why the M6 reports wrong battery percentage after a cell swap

The M6 uses a coulomb counter that builds its reference model against the original cell's discharge curve over hundreds of cycles. Swap in a new cell and that reference is stale — the IC is interpolating percentage against a curve that no longer matches the physical cell. Until the counter logs at least one full discharge from 100% to automatic shutoff and back to full charge, the percentage display will be off. Running that first cycle without fast charging gives the IC clean, low-noise data to build the new reference from.

Sudden shutdown at 20–30% on the BA711

This is a voltage cliff, not a capacity problem. When the modem transmits or the screen brightness peaks, current draw spikes sharply and the cell voltage drops faster than the fuel gauge IC expects at that state of charge. The BMS interprets the voltage drop as a hard undervoltage event and cuts power before the reported percentage reaches zero. After the first full calibration cycle, the IC re-anchors its cutoff model to the actual cell chemistry and the shutdowns stop. If they persist past two full cycles, check that the connector is fully seated — a high-resistance contact amplifies the voltage sag that triggers the cutoff.