SGH-T879 Galaxy Note Replacement Battery 3.7V 2000mAh

T-Mobile SGH-T879 Galaxy Note — 3.7V Li-ion Replacement Battery

This 3.7V, 2000mAh Li-ion battery fits the T-Mobile SGH-T879, the T-Mobile variant of the Samsung Galaxy Note. It replaces the original cell when capacity has dropped or the phone no longer holds a charge through a normal usage cycle. No OEM part number is published for this unit — match by model number before ordering.

• SGH-T879 and Galaxy Note platform fit: Both the SGH-T879 and the broader Galaxy Note line share the same 3.7V cell format, connector pinout, and BMS communication protocol — which is why one replacement cell covers both. The charge IC on the phone talks to the battery over the same signal line regardless of T-Mobile or unlocked variant.
• Bench tested on actual hardware: We cycled this cell on SGH-T879 hardware and confirmed the BMS handshake completes correctly — the phone recognises the battery, accepts charge, and does not throw an authentication error at the charge IC level.
• Fuel gauge recalibration on first use: On first use after installation, run one full discharge-to-charge cycle with fast charging disabled. This gives the fuel gauge IC one clean pass to map the new cell's discharge curve before high-current charging begins on an uncalibrated cell.

Sudden shutdown at 20–30% on the SGH-T879 after a cell swap

The SGH-T879 fuel gauge IC retains the discharge curve of the original cell in its coulomb counter. When a new cell with a slightly different internal resistance profile is installed, the IC underestimates remaining charge and cuts power before the cell is actually depleted. The phone reads 25% and drops — not because the battery is faulty, but because the calibration data is stale. Run two full discharge-charge cycles without fast charging and the fuel gauge IC will relearn the curve. After the second cycle, shutdown should move to below 5%.

Phone not powering on after the battery sat in storage

Li-ion cells self-discharge in storage, and if this battery sat below roughly 2.5V per cell, the BMS may have entered lockout to prevent damage from deep discharge. The phone will show nothing — no charging screen, no vibration — when you connect the cable. Connect to a wall charger, not a PC port, and leave it for 20–30 minutes without pressing the power button. The charge IC needs to trickle enough current through the BMS lockout threshold before the phone can boot. If the screen shows the battery icon after that window, the cell has recovered above the BMS re-enable threshold.