Meilan S6 Replacement Battery BA712 3.85V 2900mAh

Meilan S6 — 3.85V Li-Polymer Replacement Battery (BA712)

The BA712 is a 3.85V, 2900mAh lithium-polymer cell that fits the Meilan S6 smartphone. It replaces the original battery when capacity has dropped to the point where the phone can no longer hold a usable charge through a normal day. Dimensions are 72.33 × 61.90 × 3.85mm — measure your original before fitting to confirm the match.

• Meilan S6 fitment: The S6 uses a flat Li-Polymer pouch cell with a dedicated BMS board. The BA712 matches the original connector pinout and voltage rail, so the charge IC communicates correctly with the replacement cell without triggering a fault state.
• Bench tested on actual hardware: We ran the BA712 through full charge and discharge cycles on the S6 platform. The BMS accepted the cell on the first cycle, charge termination triggered correctly at 4.35V, and low-voltage cutoff activated as expected without tripping a hard lockout.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated register — preventing erratic percentage readings from the first week.

Sudden shutdown at 20–30% on the Meilan S6

This happens when the cell cannot hold its voltage above the BMS cutoff threshold under the load spikes from the modem or display. The fuel gauge IC reads a nominal state of charge, but actual terminal voltage collapses momentarily under peak current draw. It is most common in the first few cycles before the coulomb counter has a full discharge profile to work from. Run two complete discharge-charge cycles without fast charging to give the gauge IC enough data to predict the voltage cliff accurately.

OS reporting wrong battery percentage after cell swap

The fuel gauge IC on the S6 stores a learned discharge curve from the original cell. After fitting a replacement, the stored curve no longer matches the new cell's actual voltage-to-capacity relationship. The phone reads voltage correctly but maps it to the wrong percentage. One full discharge to automatic shutdown followed by an uninterrupted charge to 100% resets the coulomb counter to the new cell's curve.