Samsung BST476BKA Replacement Battery 3.7V 1100mAh

Samsung SCH-A630 / SGH-A630 — 3.7V Li-ion Replacement Battery (BST476BKA)

This is a 3.7V, 1100mAh Li-ion replacement battery for the Samsung SCH-A630 and SGH-A630 flip phones. It replaces OEM part numbers BST476BKA, BST476BKAB, and BEX476HKAB. Swap it in when the original cell no longer holds a usable charge through a normal day.

• SCH-A630 and SGH-A630 fit: Both models share the same battery bay dimensions, connector pinout, and voltage rail at 3.7V. One replacement covers either variant without modification.
• Bench tested on actual hardware: We cycled this cell through full discharge and charge sequences and confirmed the BMS communicates correctly with the charge IC — no false-full cutoff, no premature low-battery warnings during the test cycles.
• Fuel gauge recalibration on first use: After installing this cell, run one complete discharge down to automatic shutoff, then charge uninterrupted to 100% before use. The phone's fuel gauge IC was calibrated to the old cell's discharge curve — one full cycle resets it against the new cell so percentage readings stay accurate.

Why the SCH-A630 reports wrong battery percentage after a cell swap

The SCH-A630 tracks charge state using a fuel gauge IC that builds a discharge curve over multiple cycles. When you swap the physical cell, that stored curve no longer matches the new cell's actual voltage-to-capacity relationship. The gauge reads voltage and maps it to a percentage using the old data, so it can report 40% when the cell is nearly empty — or show a full bar when it isn't. One complete discharge-to-shutoff and full recharge cycle forces the IC to relearn the new cell's curve and corrects the display.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage cliff problem, not a capacity problem. Under load — active call, backlight on, cellular radio transmitting — the cell's voltage drops faster than it does at rest. If the resting voltage reads 3.55V but sags below the BMS cutoff threshold under that combined load, the phone cuts off immediately even though the percentage display showed charge remaining. The fix is the same recalibration cycle: discharge fully to automatic shutoff, then charge to 100% without interruption. After one or two full cycles the fuel gauge compensates for the sag and shutdown behavior stabilises.