SFR Starshine 3.7V Compatible Battery 1100mAh Li-ion

SFR Starshine — 3.7V Li-ion Replacement Battery

This is a 3.7V 1100mAh Li-ion replacement battery for the SFR Starshine smartphone. It fits the Starshine's original battery slot and connects to the device's charge IC and fuel gauge circuit. Capacity is 1100mAh (4.07Wh), matching the original cell specification.

• SFR Starshine fit: The Starshine uses a compact 54.00 x 43.00 x 5.00mm cell with a low-voltage Li-ion chemistry at 3.7V nominal. The connector orientation and BMS handshake are specific to this model — a cell from a different SFR handset will not seat correctly even if it looks similar.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Starshine platform. The BMS accepted the cell without fault codes, the charge IC reached full charge cleanly, and the fuel gauge IC tracked state-of-charge without erratic jumps after the first full cycle.
• First-cycle fuel gauge reset: On first use after installation, disable fast charging for one complete discharge-charge cycle. The fuel gauge IC on the Starshine is calibrated to a specific cell discharge curve. Giving it one unconstrained cycle before high-current charging lets it recalibrate accurately against the new cell.

Why the Starshine reports wrong battery percentage after a cell swap

The Starshine uses a coulomb-counter fuel gauge IC that builds its state-of-charge model from the original cell's internal resistance and discharge curve. When a new cell goes in, that learned model no longer matches actual cell behaviour. The gauge reads voltage but applies the old curve, so it can show 30% when the cell is nearly flat — or 100% when it hasn't finished charging. One full discharge down to auto-shutdown followed by a slow charge to 100% resets the curve. After that cycle, percentage reporting stabilises.

Starshine shutting off suddenly at 20–30% remaining

This is a voltage cliff failure, not a capacity problem. Under modem load or screen brightness spikes, the cell voltage drops sharply — even if the gauge shows charge remaining. The Starshine's protection circuit trips when cell voltage falls below roughly 3.0V under load, cutting power before the gauge reaches zero. A degraded or deeply discharged cell hits this cliff earlier. If the phone shuts off at 20–30% consistently, charge to 100%, run a single full cycle, and check whether the cutoff point shifts. If it doesn't, the cell has reached end of life and replacement is the correct fix.