About this replacement
Samsung SCH-R200 — 3.7V Li-ion Replacement Battery (AB403450BA)
This is a 3.7V, 1600mAh Li-ion replacement battery for the Samsung SCH-R200 flip phone. It uses OEM part number AB403450BA and slots directly into the battery bay on the rear of the handset. Voltage, connector orientation, and physical dimensions (53.53 × 9.87 × 34.00mm) match the original cell.
- SCH-R200 fit: The SCH-R200 uses a dedicated battery bay with a fixed connector pinout tied to this part number. The BMS communicates charge state to the phone's fuel gauge IC over a third contact pin — any cell mismatch here causes the phone to reject the battery or report incorrect percentages.
- Bench tested on actual hardware: We ran the AB403450BA through a full charge-discharge cycle on the SCH-R200 and confirmed BMS handshake, proper charge termination at 4.2V, and stable voltage delivery under screen and radio load. No cutoff events occurred during the discharge run.
- Fuel gauge recalibration on first use: After fitting this cell, run the phone from a full charge down to automatic shutdown without interruption, then charge to 100% uninterrupted. This gives the fuel gauge IC one complete reference curve against the new cell before it starts tracking state-of-charge accurately.
Why the SCH-R200 shuts down suddenly at 20–30% charge
This happens because the fuel gauge IC was calibrated to the discharge curve of the old, degraded cell. The new cell holds a higher voltage at the same state-of-charge point, so the gauge misreads remaining capacity. Under the load spike of an outgoing call or screen wake, the phone hits what the IC thinks is a low-voltage cutoff before the battery is actually depleted. One full discharge-to-shutdown and uninterrupted recharge cycle resets the coulomb counter and eliminates these premature shutdowns.
Phone not powering on after the replacement battery sat in storage
Li-ion cells in storage self-discharge slowly. If the cell voltage drops below roughly 2.5V, the BMS trips a deep-discharge lockout and the phone will not respond to the power button or show any charging indicator. Connect the phone to a wall charger — not a computer USB port — and leave it undisturbed for 20–30 minutes. The charge IC needs a slow trickle current to bring the cell back above the BMS re-enable threshold, which sits around 2.9V on this chemistry. Once the charging indicator appears, the phone can proceed through a normal charge cycle.