LG KG920 Replacement Battery 3.7V 650mAh Li-ion

LG KG920 / KG928 — 3.7V Li-ion Replacement Battery

This is a 3.7V, 650mAh Li-ion cell for the LG KG920 and KG928 candybar-style phones. It slots into the same compartment as the original and connects to the same three-contact terminal. Capacity matches OEM spec at 2.41Wh.

• KG920 and KG928 compatibility: Both models share the same battery bay dimensions, three-pin contact layout, and 3.7V nominal voltage rail. The BMS handshake is identical across both, so one cell covers either handset.
• Bench tested on actual hardware: We cycled this cell through charge and load on the KG920 platform. The BMS accepted the charge current without tripping, and the protection circuit cut off cleanly at the low-voltage threshold under a simulated call load.
• Fuel gauge recalibration on first install: After fitting this cell, run one full discharge down to auto-shutdown, then charge uninterrupted to 100% before normal use. The KG920 uses a basic coulomb counter that was calibrated to your old, degraded cell — skipping this step causes the percentage display to drift or cut out early on the replacement.

Sudden shutdown at 20–30% on the KG920 after a cell swap

This happens because the fuel gauge IC still holds the discharge curve from the worn-out original cell. When the new cell hits its real voltage cliff — around 3.4–3.5V under modem or screen load — the phone shuts down even though the percentage counter claims charge remains. The fix is one complete discharge-to-shutdown followed by a full charge. After that single calibration cycle, the coulomb counter resets its endpoint and the reported percentage tracks the actual cell voltage correctly.

Phone warm near the battery slot on the first charge after replacement

A new Li-ion cell arrives with higher internal impedance than a broken-in cell. On the first charge, the charge IC pushes current into that higher-impedance cell, which converts more energy to heat than usual. This is normal on cycle one and settles from cycle two onward as the cell's impedance drops. If warmth persists past the third full charge, check that the battery cover is seated flush — trapped heat with no airpath will extend this effect.