Samsung BST2389SE Replacement Battery 3.7V 1000mAh

Samsung SPH-600 / SPH-A600 — 3.7V Li-ion Replacement Battery (BST2389SE)

This is the BST2389SE Li-ion cell at 3.7V and 1000mAh, sized for the Samsung SPH-600 and SPH-A600 handsets. It slots into the same battery bay as the original and connects to the same charge IC and fuel gauge circuit. Use the capacity figure from this listing — 1000mAh — not third-party specs you may find elsewhere.

• SPH-600 and SPH-A600 compatibility: Both models share the same battery bay dimensions, connector pinout, and BMS handshake protocol. One cell covers both devices without adapter or modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the SPH platform. The BMS accepted the charge IC handshake cleanly, and the protection circuit tripped correctly at low-voltage cutoff — no false lockouts during the test sequence.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. The fuel gauge IC calibrates its internal model against the new cell's discharge curve. Skipping this step lets the coulomb counter carry over stale data from the old cell, which causes erratic percentage readings from day one.

Sudden shutdown at 20–30% on the BST2389SE replacement cell

This happens because the fuel gauge IC still holds the discharge curve from the degraded original cell. When the new cell's terminal voltage drops under modem transmit or screen load, it hits a voltage point the IC wasn't expecting — the phone interprets it as a critical low and shuts down even though the displayed percentage reads higher. It is not a defective cell. Run one full discharge to automatic shutdown, then charge uninterrupted to 100% without fast charging active. After that cycle, the coulomb counter resets against the actual new cell curve and the shutdowns stop.

Phone not powering on after the BST2389SE sat in storage

Li-ion cells self-discharge in storage, and if the cell drops below roughly 2.5V, the BMS enters a lockout state to prevent further discharge damage. The phone will show nothing — no charging animation, no boot screen — when you first connect it. Connect the phone to a wall charger rather than a PC USB port, which may not supply enough current to push the cell past the BMS recovery threshold. Leave it on charge for 15–20 minutes before attempting to power on. If the cell recovers, the charging animation will appear and the phone will boot normally once voltage climbs above 3.0V.