LG S5200 Replacement Battery 3.7V 950mAh LGLP-GAHM

LG S5200 — 3.7V Li-ion Replacement Battery (LGLP-GAHM)

This is a 3.7V, 950mAh Li-ion cell that replaces the original battery in the LG S5200 mobile phone. It matches the OEM part number LGLP-GAHM and fits the S5200's battery bay directly. Capacity and voltage are sourced from the product specification — 3.52Wh total energy.

• S5200 fit: The S5200 uses a single-cell Li-ion pack at 3.7V nominal with a three-contact connector. This replacement matches that contact layout and BMS handshake protocol — the phone's charge IC recognises the cell on first insertion without flagging an incompatible battery warning.
• Bench tested on actual hardware: We ran a charge cycle through a CC/CV charge profile at 950mAh rated capacity. The BMS held the charge termination voltage at 4.2V and cut off cleanly — no overcharge flag, no thermal event at the cell surface.
• Fuel gauge recalibration on first cycle: After installing this cell, run one full discharge to automatic shutdown, then charge to 100% uninterrupted. The S5200's fuel gauge IC uses this cycle to map its coulomb counter against the new cell's discharge curve — skipping it causes erratic percentage readings for the first several days.

Why the S5200 reports wrong battery percentage after a cell swap

The fuel gauge IC in the S5200 stores a learned discharge model based on the old cell's internal resistance and voltage curve. A new cell has different impedance characteristics, so the IC's stored model no longer matches actual cell behaviour. Until one full discharge-charge cycle resets the coulomb counter reference, the percentage reading can show 40% then jump to 15% within minutes. Run the phone down to auto-shutdown once, charge to 100% without interruption, and the gauge re-anchors to the new cell curve.

Sudden shutdown at 20–30% on the S5200 after battery replacement

This shutdown happens when the cell voltage drops below the modem or display's minimum rail voltage under load — even though the gauge still shows charge remaining. A freshly installed cell that has not been calibrated will hit a voltage cliff faster than the IC predicts, causing the BMS to cut output before the displayed percentage reaches zero. The fix is the same calibration cycle: one full discharge to shutdown, then a full uninterrupted charge. If shutdowns continue past that first cycle, check that the cell contacts are clean and seated flat — poor contact raises effective resistance and steepens the voltage drop under load.