LGIP-340N LG KF900 Replacement Battery 3.7V 950mAh

LG KF900 / KS660 Series — 3.7V Li-ion Replacement Battery (LGIP-340N)

This is a 3.7V, 950mAh Li-ion replacement battery for the LG KF900, KF900 PRADA II, KS660, KS500, and over 30 additional LG handsets using the LGIP-340N cell format. It matches the original cell's voltage, contact layout, and physical dimensions (62.65 × 38.90 × 4.90mm). Fit the battery and the phone powers on — no tools required beyond removing the back cover.

• KF900 and KS-series compatibility: These handsets share the same battery bay dimensions, three-contact connector pinout, and 3.7V nominal voltage rail. The LGIP-340N fits all of them without modification because LG used a common battery platform across this touchscreen-slider generation.
• Bench tested on actual hardware: We cycled this cell through full charge-discharge on a KF900 unit and monitored BMS cutoff thresholds. The protection circuit tripped correctly at low voltage and the charge IC accepted a standard USB charge input without fault flags.
• Fuel gauge recalibration on first install: On first use after fitting this battery, run the phone down to automatic shutdown, then charge it to 100% without interruption. The KF900's fuel gauge IC calibrates its coulomb counter against the new cell's actual discharge curve during that first full cycle — skip it and the percentage readout will be inaccurate from the start.

Sudden shutdown at 20–30% on the KF900 after a cell swap

The KF900's fuel gauge IC stores a discharge model built on the old cell's internal resistance profile. When a fresh cell with lower impedance goes in, the IC underestimates how much capacity remains near the bottom of the curve. The phone's modem or backlight pulls current, the cell voltage briefly dips below the shutdown threshold the IC is watching for, and the phone cuts off — even though the cell still has usable charge. Running one complete uninterrupted discharge-to-charge cycle forces the coulomb counter to remap against the new cell. After that cycle, shutdowns at 20–30% stop.

Phone feels warm near the battery compartment on the first few charges

A new Li-ion cell starts with slightly higher internal impedance than a cell that has been cycled. During the first few charges, the charge IC deposits energy into that higher-resistance cell and some of that energy dissipates as heat — this is normal and temporary. Warmth concentrated at the battery cover, not the USB port or processor area, is the sign this is charge-related rather than a fault. It settles after two or three full cycles as the cell's internal resistance drops. If the phone stays hot after five cycles, check that the back cover is seated flush and not trapping heat against the battery.