LG KU310 Replacement Battery 3.7V 650mAh Li-ion

LG KU310 / KG311 — 3.7V Li-ion Replacement Battery

This is a 3.7V, 650mAh (2.41Wh) Li-ion replacement battery for the LG KU310 and KG311 mobile phones. It slots into either handset to restore power when the original cell has degraded or stopped holding a charge. Fit model and voltage match the original spec directly.

• KU310 and KG311 compatibility: Both models share the same battery bay dimensions, connector pinout, and 3.7V nominal voltage rail, so a single cell covers both. The BMS handshake on each device accepts the same charge profile, no firmware differences affect charging behaviour.
• Bench tested on actual hardware: We cycled this cell through a full discharge and charge sequence, confirming the BMS accepted the charge profile without cutoff events and that voltage held stable under simulated call and screen load.
• Fuel gauge recalibration on first use: On first use after installation, disable any fast-charge mode and run one complete discharge-to-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's discharge curve before high-current charging begins on an uncalibrated cell.

Why the KU310 reports wrong battery percentage after a cell swap

The KU310 uses a fuel gauge IC that 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 IC reads voltage and maps it to the old curve, producing percentage figures that are off — sometimes by 15–20%. One full discharge down to automatic cutoff followed by a full charge resets the reference data the gauge uses. After that cycle, reported percentage tracks closely with actual remaining capacity.

Sudden shutdown at 20–30% on the replacement cell

This happens when the fuel gauge IC is still calibrated to a worn cell with a shallow voltage cliff. The new cell has a steeper voltage drop near depletion, and under modem or screen load, terminal voltage dips below the protection threshold before the gauge shows 0%. The phone interprets that voltage sag as a fault and cuts power. Run one full supervised discharge cycle — let the phone shut itself off naturally — then charge to 100% without interruption. After that cycle the gauge recalibrates and the early-shutdown behaviour stops.