LGIP-G830 LG KG120 Replacement Battery 3.7V 850mAh

LG KG120 / KP202 Series — 3.7V Li-ion Replacement Battery (LGIP-G830)

This is a 3.7V 850mAh Li-ion cell built to the LGIP-G830 spec. It fits the LG KG120, KP202, KG202, and NX225 feature phones. Slot it in when the original cell no longer holds a charge or the phone shuts down unexpectedly.

• KG120 / KP202 platform fit: These models share the same battery bay dimensions, connector pinout, and 3.7V nominal rail. One cell covers all four devices without modification.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on a KP202 unit. The BMS accepted the cell without fault flags, and the protection circuit tripped correctly at low-voltage cutoff during the drain test.
• Fuel gauge recalibration on first use: After fitting, run the phone down to auto-shutdown on its own — do not force-off. Then charge uninterrupted to 100%. This gives the fuel gauge IC one full reference cycle against the new cell's discharge curve before the OS starts reporting capacity accurately.

Why the KG120 reports wrong battery percentage after a cell swap

The fuel gauge IC on these LG feature phones stores a learned discharge curve from the original cell. When a new cell goes in, that stored curve no longer matches the actual voltage-to-capacity relationship of the replacement. The phone reads voltage and maps it to the old curve, so the percentage shown can be off by 15–25%. One complete discharge-to-shutdown followed by an uninterrupted charge to 4.2V resets the reference point and brings the readout back into alignment.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops below what the phone's load can sustain, even though the fuel gauge still shows charge remaining. At 20–30% state of charge, the cell voltage on an uncalibrated gauge sits near 3.6–3.7V at rest but sags under the transmit or backlight load. The BMS reads an undervoltage event and cuts output before the gauge catches up. Let the phone discharge fully to shutdown twice in a row — this forces the coulomb counter to relearn the actual usable voltage window of the new cell.