Samsung SCH-A570 Replacement Battery BST383ADA 3.7V 1000mAh

Samsung SCH-A570 — 3.7V Li-ion Replacement Battery (BST383ADA)

The BST383ADA is a 3.7V, 1000mAh Li-ion cell that fits the Samsung SCH-A570 mobile phone. It restores power to the handset when the original cell no longer holds a usable charge. Capacity is 3.7Wh, matching the original specification.

• SCH-A570 fit: This cell matches the voltage rail, physical form factor, and connector orientation the SCH-A570 requires. The BMS handshake on this phone expects a 3.7V nominal cell — a mismatched voltage causes the device to reject the battery entirely or report erratic percentages from the first boot.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the SCH-A570 platform and monitored BMS response at each stage. The protection circuit held cutoff correctly at the low-voltage threshold, and the charge IC accepted the cell without fault flags.
• Fuel gauge recalibration after swap: On first use, disable any power-saving shortcuts and run one complete discharge down to automatic shutoff, then charge uninterrupted to 100%. This gives the fuel gauge IC one full reference cycle against the new cell's discharge curve before it starts reporting accurate percentages.

Why the SCH-A570 reports wrong battery percentage after a cell swap

The SCH-A570 uses a fuel gauge IC that builds its percentage estimate from a stored discharge curve tied to the original cell. When a new cell goes in, that stored curve no longer matches the actual voltage-to-capacity relationship of the replacement. The gauge reads voltage correctly but maps it to the wrong percentage point on the old curve. One full discharge-to-shutoff and uninterrupted recharge resets the reference and brings the displayed percentage back in line.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops sharply under load — calls, backlight, and radio transmit all pull current simultaneously, and a cell that hasn't been calibrated yet hits the BMS low-voltage cutoff before the display percentage catches up. The phone reads 25% but the cell is already below the 3.0V protection threshold under that combined load. It isn't a faulty cell — it's an uncalibrated gauge mapping charge state incorrectly. Run one complete cycle as described above; after calibration, the shutoff will align with the displayed percentage.