BP-F01 Phicomm FWS610 Compatible Battery 3.7V 1300mAh

PHICOMM FWS610 / FWS810 — 3.7V Li-ion Replacement Battery (BP-F01)

This is a 3.7V, 1300mAh Li-ion replacement battery for the PHICOMM FWS610 and FWS810 smartphones. It replaces OEM part BP-F01 when the original cell can no longer hold a charge through daily use. Dimensions are 58.95 × 48.20 × 4.40mm — measure your existing cell before ordering if the back cover shows any swelling.

• FWS610 and FWS810 compatibility: Both models share the same battery bay dimensions, connector pinout, and BMS handshake protocol under the BP-F01 spec, so one cell covers either device without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the FWS810 platform. The BMS accepted the cell without a low-voltage lockout event, and the charge IC brought it to 4.2V cutoff cleanly on the first cycle.
• Fuel gauge recalibration on first use: After installation, run one full discharge to 10% then charge uninterrupted to 100% before enabling fast charging. This gives the fuel gauge IC a complete reference curve for the new cell — skipping it causes the percentage counter to drift from the first day.

Why the FWS610 reports wrong battery percentage after a cell swap

The fuel gauge IC on the FWS610 stores a learned discharge curve for the old 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, so the percentage displayed can be off by 10–20 points. One full uninterrupted discharge-charge cycle forces the IC to rewrite the reference curve against the new cell and typically resolves the drift.

Sudden shutdown at 20–30% on the FWS810 after replacement

This happens when the display or modem draws a short burst of current and the cell voltage drops below the BMS cutoff threshold — even though the gauge still shows charge remaining. It is a voltage cliff issue, not a capacity fault. The cell voltage under load dips below 3.2V, the BMS trips, and the phone shuts off. Running that initial full calibration cycle firms up the fuel gauge's low-end voltage mapping, which reduces the gap between displayed percentage and the actual cutoff point.