Gigaset ME Pro Replacement Battery 3.85V 4000mAh

Gigaset ME Pro / GS57-6 — 3.85V Li-Polymer Replacement Battery (GI02)

This 3.85V, 4000mAh Li-Polymer cell replaces the original GI02 battery in the Gigaset ME Pro and GS57-6 smartphones. It restores full power capacity to the device when the original cell has degraded or stopped holding charge. Voltage and capacity match OEM spec exactly — no modifications needed for installation.

• ME Pro and GS57-6 fit: Both models use the same battery bay dimensions and the same GI02 connector pinout. The 81.30 × 66.50 × 4.20mm cell profile fits the chassis without pressure on the mid-frame, and the BMS handshake matches the charging IC on both boards.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the GS57-6 board. The BMS accepted the cell without fault flags, charge current ramped correctly through CC/CV phases, and the protection circuit tripped at the expected low-voltage cutoff.
• First-cycle calibration on the ME Pro: On first use after installation, disable fast charging and run 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 cell — preventing percentage jumps in the first week.

Sudden shutdown at 20–30% on the Gigaset ME Pro after a cell swap

This happens because the fuel gauge IC is still running the discharge curve from the old, degraded cell. The new cell has a steeper voltage cliff under modem and display load, so the phone hits the hardware undervoltage threshold before the OS reads 0%. The fix is one full uninterrupted discharge down to automatic power-off, followed by a full charge to 100% without interruption. After that cycle, the coulomb counter recalibrates to the new cell's actual curve and the shutdowns stop.

Phone warm near the battery during the first two charges after replacement

A new Li-Polymer cell has higher internal impedance than a broken-in cell. The charge IC pushes the same current profile it used on the old cell, which generates more heat across the higher resistance of the fresh cell. This is normal for the first two to three cycles and temperature drops as impedance settles. If the phone stays warm beyond the third full charge, check that nothing is blocking the back cover ventilation gap and that ambient temperature is below 35°C during charging.