Samsung Galaxy Grand 3 EB-BG720CBC 3.7V Replacement Battery

Samsung Galaxy Grand 3 — 3.7V Li-ion Replacement Battery (EB-BG720CBC)

This is a 3.7V, 2200mAh Li-ion replacement battery for the Samsung Galaxy Grand 3 and Grand 3 Duos smartphones. It fits SM-G720AX, SM-G7200, and related SM-G720 variants. Swap it in when the original cell no longer holds a charge or causes unexpected shutdowns.

• SM-G720 series fitment: The Grand 3 and Grand 3 Duos share the same battery bay geometry, connector pin-out, and BMS handshake requirements. Both single-SIM and Duos variants draw from the same 3.7V rail, so one cell covers the full SM-G720 lineup without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on SM-G7200 hardware. The BMS accepted the charge IC handshake on the first cycle, voltage held steady across screen-on and modem-active load states, and cutoff triggers fired within spec at both ends of the curve.
• First-cycle fuel gauge recalibration: On first use after installation, disable fast charging and run one complete discharge-charge cycle at standard current. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before high-current charging is applied to an uncalibrated cell.

Sudden shutdown at 20–30% on the replacement cell

The Grand 3's fuel gauge IC holds a discharge curve calibrated to the original cell. A new cell with a slightly different internal resistance profile hits a voltage cliff earlier under modem or display load than the IC expects. The phone reads 25% remaining but the cell voltage has already dropped below the safe-operation threshold. One full discharge-to-shutoff followed by an uninterrupted charge to 100% resets the coulomb counter and brings the percentage reading back into alignment with actual cell state.

Device not powering on after the battery sat in storage

Li-ion cells self-discharge in storage. If this battery was stored discharged for an extended period, the cell voltage may have fallen below 2.5V — the threshold at which the BMS latches into lockout to prevent damage. The phone will show no response to the power button and may not register on a charger immediately. Connect to a wall charger at 5V and leave it for 20–30 minutes; the charge IC will trickle current into the cell until the BMS re-initialises above 2.8V, after which normal charging resumes.