Samsung EB485159LA SPH-M950 Replacement Battery 3.7V 3600mAh

Samsung Galaxy Reverb / SPH-M950 — 3.7V Li-ion Replacement Battery (EB485159LA)

This is a 3.7V, 3600mAh Li-ion replacement cell for the Samsung SPH-M950, sold under the Galaxy Reverb name on Sprint. It matches the OEM part number EB485159LA and fits the full SPH-M950DAAVMU variant as well. Install it when the original cell no longer holds voltage under screen or modem load.

• SPH-M950 and Galaxy Reverb compatibility: Both retail names reference the same hardware platform — same connector, same BMS handshake voltage, same charge IC expectations. One cell covers all three fit-model designations listed by Samsung.
• Bench tested on actual hardware: We cycled this cell through charge, full discharge, and a second charge on SPH-M950 hardware. The BMS accepted the charge IC handshake on first contact and held voltage within spec across the discharge curve.
• Fuel gauge recalibration on first cycle: After fitting this cell, disable fast charging and run one full discharge down to automatic shutdown, then charge to 100% uninterrupted. The fuel gauge IC calibrates its coulomb counter against the new cell's discharge curve during that first cycle — skipping it causes erratic percentage readings for days.

Why the SPH-M950 reports wrong battery percentage after a cell swap

The SPH-M950 uses a fuel gauge IC that builds its charge model from the previous cell's discharge history. When a new cell goes in, the IC still references the old degraded curve. This mismatch causes the percentage display to jump or stall — the hardware is fine, the lookup table is wrong. One complete discharge-charge cycle forces the coulomb counter to rebuild against the new cell's actual voltage-capacity profile. After that cycle, percentage accuracy returns to normal.

Sudden shutdown at 20–30% on the replacement cell

This happens when the modem transmits or the screen peaks brightness — both draw current fast enough to collapse cell voltage below the BMS cutoff threshold, even though the reported percentage looks safe. The fuel gauge IC reads average voltage, not instantaneous sag, so 25% displayed can still trigger a hard cutoff under load. Complete two full discharge-charge cycles first; this lets the IC map the new cell's internal resistance and adjust sag prediction. If shutdown persists below 20%, check that the battery connector pins are fully seated — a partial connection raises contact resistance and worsens voltage sag.