Samsung SCH-A930 Replacement Battery 3.7V 850mAh Li-ion

Samsung SCH-A930 / SPH-A960 Series — 3.7V Li-ion Replacement Battery (AB553446GABSTD)

This is a 3.7V 850mAh Li-ion cell replacing the original battery in Samsung's early flip phone lineup. It fits the SCH-A930, SPH-A960, SCH-A990, and SPH-A640 among others. Voltage and physical dimensions match OEM spec — 49.50 × 33.80 × 4.70mm.

• Cross-model fit — SCH and SPH series: These Samsung flip phones share the same battery footprint, connector orientation, and 3.7V single-cell architecture. The AB553446GA cell family was used across both CDMA variants, so one part number covers the full group without modification.
• Bench tested on actual hardware: We cycled this cell through full discharge and charge on the SCH-A930. The BMS accepted charge from a standard 5V source without tripping into protection mode, and the phone powered through startup without a low-voltage cutoff event.
• Fuel gauge recalibration on first use: After installing a fresh cell, run one complete discharge down to automatic shutdown, then charge uninterrupted to 100% before normal use. The phone's fuel gauge IC was calibrated to the wear curve of the old cell — skipping this step causes erratic percentage readings from the first day.

Why the SCH-A930 reports wrong battery percentage after a cell swap

Samsung's flip phone fuel gauge IC builds a discharge model based on how the installed cell behaves over repeated cycles. When you replace the cell, that internal model still reflects the old battery's degraded curve — not the new one. The gauge then misreads state-of-charge, often showing 100% for too long then dropping sharply. One full discharge-charge cycle forces the IC to relearn the new cell's actual voltage-to-capacity relationship and corrects the display.

Sudden shutdown at 20–30% on the replacement cell

This happens when the fuel gauge IC still maps the old cell's steep voltage cliff onto the new cell. The phone reads 25% remaining but the uncalibrated gauge misses the actual cutoff threshold, and the processor shuts down to protect the cell. It is not a defective battery — it is a calibration mismatch. Force a full discharge to automatic shutdown, charge back to 100% without interruption, and the cutoff behaviour corrects itself. After that cycle, the gauge trips the shutdown closer to the true 3.0V per cell floor.