SFR Starshine 3.7V Li-ion Replacement Battery 1300mAh

SFR Starshine — 3.7V Li-ion Replacement Battery

This is a 3.7V, 1300mAh Li-ion cell for the SFR Starshine smartphone. It replaces the original battery when the cell has degraded and can no longer hold a usable charge. Dimensions are 54.00 x 43.00 x 5.00mm — confirm these against your existing cell before fitting.

• SFR Starshine fit: The Starshine uses a compact removable cell format at 3.7V nominal. This replacement matches that voltage rail and physical footprint, so the connector seats without modification and the BMS handshake completes on first boot.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench, confirmed BMS communication, and verified the protection circuit trips correctly at both the high and low voltage thresholds before shipment.
• Fuel gauge recalibration tip: On first use after installation, run one complete discharge down to auto-shutoff, then charge uninterrupted to 100% before resuming normal use. This gives the fuel gauge IC a full reference curve against the new cell and prevents erratic percentage readings in the first few days.

Why the Starshine reports wrong battery percentage after a cell swap

The Starshine's fuel gauge IC builds its charge estimate from a stored discharge curve calibrated to the original cell. When you install a new cell, that stored curve no longer matches actual cell behaviour. The IC continues referencing old data, so the percentage shown can be 10–20% off in either direction. One full discharge-to-shutoff followed by a complete charge resets the reference point and brings the reported percentage back into line.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops below the modem's or display's minimum rail voltage under load, even though the fuel gauge still reads a healthy percentage. The new cell's internal resistance under a real load causes a sharper voltage sag than the old degraded cell the IC was calibrated to. The BMS interprets this voltage cliff as a critical low and cuts output before the percentage reaches zero. Running one full calibration cycle as described above reduces the frequency of these premature cutoffs — the fuel gauge then tracks the actual cliff point of the new cell.