About this replacement
Samsung Galaxy Grand 2 / SM-G7102 — 3.8V Li-ion Replacement Battery (EB-B220AC)
This is a 3.8V, 2600mAh lithium-ion replacement battery for the Samsung Galaxy Grand 2 and Galaxy Grand 2 Duos, covering SM-G7102, SM-G7106, and related variants. It replaces OEM part numbers EB-B220AC and EB665468LU. The cell fits the original battery compartment and connects to the same charging and protection circuitry already in the phone.
- Grand 2 and Duos compatibility: The SM-G7102 and SM-G7106 share the same battery bay dimensions, connector pinout, and BMS handshake requirements. One cell covers both single-SIM and Duos variants without modification.
- Bench tested on actual hardware: We ran this cell through a full charge cycle on an SM-G7102 and confirmed the BMS accepted charge without triggering overcurrent cutoff. The fuel gauge IC registered cell voltage correctly at the start of the first cycle.
- First-cycle calibration tip: On first use after installation, disable fast charging and run one complete discharge-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging begins against an uncalibrated reference.
Why the Galaxy Grand 2 reports wrong battery percentage after a cell swap
The Grand 2 uses a coulomb-counting fuel gauge IC that builds its capacity model around the cell it has been cycling against. When a new cell goes in, the IC still references the old discharge curve, so the percentage reading drifts from the actual state of charge. The gauge needs at least one full discharge down to automatic shutdown and one full charge to 4.2V to recalibrate its reference points. Until that cycle completes, readings anywhere in the 20–80% range can be off by 10–20 percentage points. Run that first full cycle before trusting the percentage indicator.
Sudden shutdown at 20–30% remaining on the replacement cell
This is a voltage cliff, not a calibration error — the cell cannot hold voltage above the BMS cutoff threshold when the modem transmits or the screen drives peak current. It happens most often in the first few cycles before the cell has been conditioned and before the fuel gauge IC has an accurate low-end reference. The BMS cuts power to protect the cell even though the displayed percentage still shows charge remaining. Discharge the phone fully to automatic shutdown twice, recharge to 100% each time, and the low-voltage behaviour should stabilise above the 3.2V cutoff point.