T-Mobile EB484659VA Smartphone Replacement Battery 3.7V 1200mAh

T-Mobile EB484659VA — 3.7V Li-ion Replacement Battery

This is a 3.7V 1200mAh Li-ion cell that replaces the original T-Mobile EB484659VA battery. It fits devices that draw from this battery platform, restoring power for calls, messaging, and mobile data. Voltage and capacity match the OEM spec exactly — no modification needed for installation.

• EB484659VA platform compatibility: Samsung-manufactured cells under this OEM part number share a standardised connector pinout and BMS handshake profile. The replacement cell carries the same BMS communication lines, so the host device recognises the battery without triggering a hardware fault.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the bench, monitoring BMS cutoff behaviour at both the high and low voltage thresholds. The protection circuit tripped correctly at the low-voltage floor with no latching fault observed.
• Fuel gauge recalibration after swap: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle at standard current. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated state.

Why the phone reports wrong battery percentage after a cell swap

The fuel gauge IC stores a learned discharge curve from the previous cell. When a new cell goes in, that stored curve no longer matches actual cell chemistry or capacity. The IC then interpolates percentage against the wrong baseline, producing readings that jump or plateau at incorrect values. One full discharge-charge cycle at standard current forces the coulomb counter to reset and remap against the replacement cell.

Sudden shutdown at 20–30% on the replacement cell

This happens when the modem or display pulls a high current burst and the cell voltage drops sharply below the BMS cutoff threshold — even though the reported percentage looks safe. The fuel gauge is reading an averaged voltage, not the instantaneous sag under load. A freshly installed cell with an uncalibrated gauge is most vulnerable to this on the first few cycles. Let the phone complete two full discharge-charge cycles and the gauge will track the voltage cliff accurately enough to warn before shutdown.