About this replacement
LG W5200 — 3.7V Li-ion Replacement Battery (BSP-16G)
This is a 3.7V, 650mAh Li-ion replacement battery for the LG W5200 mobile phone. It replaces OEM part number BSP-16G directly. Use it when the original cell no longer holds a charge or the phone shuts down unexpectedly under load.
- W5200 platform fit: The W5200 uses a single-cell 3.7V Li-ion configuration with a fixed connector footprint tied to the BSP-16G form factor. This replacement matches that connector, cell voltage, and BMS handshake so the phone's charge IC accepts the cell without flagging an incompatibility error.
- Bench tested on actual hardware: We cycled this cell through charge and discharge under standard smartphone load conditions. The BMS held cutoff voltage correctly at both ends — no early termination on charge, no undervoltage collapse on discharge.
- Fuel gauge recalibration on first cycle: On first use after installation, run one complete discharge down to automatic shutdown, then charge to 100% without interruption. This gives the fuel gauge IC a full reference curve against the new cell — skipping this step is the most common reason percentage jumps erratically in the first week.
Why the W5200 reports wrong battery percentage after a cell swap
The fuel gauge IC in the W5200 tracks charge state using a coulomb counter calibrated to the discharge curve of the original cell. When a new cell goes in, the counter still references old data. The phone can read 40% remaining when the actual cell voltage is already dropping toward cutoff. One full uninterrupted discharge-charge cycle forces the IC to relearn the new cell's curve and brings the percentage display back in line with real capacity.
Sudden shutdown at 20–30% on the replacement cell
This happens when the cell voltage drops below what the phone's processor and modem require under peak load — even if the displayed percentage still looks healthy. The W5200's charge IC uses a voltage threshold around 3.5V to trigger emergency shutdown, and a new cell with a steeper discharge curve than the original hits that threshold sooner than the gauge expects. After the first full calibration cycle, the shutdown point typically shifts back to the correct range. If shutdowns continue past the second full cycle, check that the cell seated correctly and the connector is fully latched.