Samsung SCH-S200 Replacement Battery BSL1307WE 3.7V 1000mAh

Samsung SCH-S200 / SCH-S208 — 3.7V Li-ion Replacement Battery (BSL1307WE)

This is a 3.7V, 1000mAh Li-ion battery that directly replaces the BSL1307WE cell in the Samsung SCH-S200 and SCH-S208 mobile phones. It restores power to devices where the original cell has degraded and no longer holds a usable charge. Voltage and capacity match the original spec exactly.

• SCH-S200 and SCH-S208 compatibility: Both models run the same 3.7V single-cell architecture with an identical connector pinout and BMS handshake. One cell covers both variants without modification.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the SCH-S200 platform. The BMS accepted the cell, charge termination triggered correctly at 4.2V, and the protection circuit tripped as expected at the low-voltage cutoff threshold.
• Fuel gauge recalibration on first use: After fitting this cell, disable any fast-charge mode and run one full discharge-to-charge cycle before normal use. The phone's fuel gauge IC is calibrated to the old cell's discharge curve — one clean cycle lets it map the new cell's characteristics and report accurate percentages.

Why the SCH-S200 reports wrong battery percentage after a cell swap

The SCH-S200 uses a fuel gauge IC that tracks charge state by measuring the discharge curve of the installed cell over time. When you fit a new cell, the IC still references the curve it mapped from the old, degraded battery. The percentage reading will appear inaccurate — often showing full charge, then jumping down unexpectedly — until the IC re-learns the new curve. One complete discharge from 100% down to automatic cutoff, followed by a full charge, resets the calibration. After that cycle, the percentage display tracks the actual cell state correctly.

Sudden shutdown at 20–30% on the replacement cell

This happens when the fuel gauge IC hasn't yet calibrated to the new cell's voltage-to-capacity curve — the phone cuts power not because the cell is truly empty, but because the voltage reading at that state of charge falls outside what the uncalibrated IC expects. It's a software-side mismatch, not a fault with the cell itself. Run the phone down until it shuts off on its own, then charge uninterrupted to 100% without interruption. After that single calibration cycle, the shutdowns at 20–30% typically stop.