LG BSL-61G 4010 Replacement Battery 3.7V 800mAh

LG 4010 / G4010 Series — 3.7V Li-ion Replacement Battery (BSL-61G)

This is a 3.7V, 800mAh Li-ion replacement battery carrying OEM part number BSL-61G. It fits the LG 4010, G4010, 4011, and G4011 mobile phones. Capacity figure is taken from product data — 800mAh (2.96Wh).

• 4010 / G4010 / 4011 / G4011 compatibility: These four models share the same battery bay geometry, connector pinout, and BMS handshake protocol. The BSL-61G cell meets the voltage rail and communication requirements across the entire group — no hardware modification needed.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the 4010 platform. The BMS accepted the cell on first insertion, charge termination triggered correctly at full voltage, and the protection circuit tripped as expected on overcurrent simulation.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This allows the fuel gauge IC to recalibrate against the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell.

Why the LG 4010 reports wrong battery percentage after a cell swap

The LG 4010 uses a fuel gauge IC that builds its charge model around the discharge curve of the original cell. When a new cell goes in, the IC is still referencing the old cell's internal resistance and capacity profile. The percentage readout will drift — often showing full charge when the cell is partially depleted, or dropping sharply mid-session. One full uninterrupted discharge down to shutdown followed by a full charge resets the coulomb counter and realigns the gauge to the new cell curve.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage cliff issue, not a capacity fault. Under load from the modem or display, cell voltage drops faster than the fuel gauge anticipates — the phone shuts down before the gauge reaches 0%. It happens most often in the first two or three cycles on a new cell because the gauge IC hasn't mapped the new cell's voltage sag curve yet. Run two full discharge-charge cycles without interruption. After that, the gauge recalibrates and shutdowns before 20% should stop. If they continue past cycle three, check that resting voltage after a full charge reads at or above 4.1V.