Samsung AB463651GZ Replacement Battery 3.7V 850mAh

Samsung SCH-U960 / SCH-U450 — 3.7V Li-ion Replacement Battery (AB463651GZ)

This is a 3.7V, 850mAh Li-ion replacement battery for the Samsung Reclaim (SCH-U960) and Intensity (SCH-U450) flip phones. It uses OEM part number AB463651GZ and fits the full compatibility list including the Rogue U960. Voltage and cell dimensions match the original spec: 54.20 × 36.00 × 4.70mm.

• SCH-U960 and SCH-U450 platform fit: Both devices share the same battery bay geometry, contact rail, and 3.7V nominal voltage requirement. The connector seats identically across the Reclaim, Intensity, and Rogue variants, so one cell covers the full model group without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on an SCH-U450 and monitored BMS cutoff behaviour at both ends of the voltage curve. The protection circuit tripped correctly at the low-voltage threshold and accepted charge without fault flags at 4.2V termination.
• Fuel gauge recalibration on first cycle: After fitting this cell, run one full discharge down to auto-shutdown, then charge uninterrupted to 100% before normal use. The SCH-U960 and U450 both use a basic coulomb counter that anchors its calibration points to the first complete cycle — skipping this step causes the gauge to report inaccurate percentages from the start.

Sudden shutdown at 20–30% on the SCH-U960 after a cell swap

This is a voltage cliff, not a capacity problem. The SCH-U960's processor and radio draw a combined current spike during transmission that a partially discharged Li-ion cell cannot sustain without voltage sag. When cell voltage dips below the BMS protection threshold under that load — even briefly — the circuit cuts power to protect the cell. The percentage shown on screen is a fuel gauge estimate, not a real-time voltage reading, so the phone appears to have charge left when the cell can no longer hold voltage under load. Let the phone run a full discharge-to-shutdown cycle on the new cell so the coulomb counter maps the actual discharge curve.

Phone reports 100% immediately after installation without charging

The fuel gauge IC on these Samsung flip phones stores the last known charge state in memory. When a new cell is installed, the IC reads its stored value rather than measuring the new cell, so it can display a full or near-full percentage that does not reflect actual cell state. This is not a battery fault — it is the gauge referencing stale calibration data. Discharge the phone to auto-shutdown once and then charge to 100% in a single uninterrupted session to force the IC to write new endpoints. After that cycle, percentage readings will track the actual cell voltage correctly.