Huawei HB4A3 G6620 Replacement Battery 3.7V 800mAh

Huawei G6620 / T1201 / T1209 / G7210 — 3.7V Li-ion Replacement Battery (HB4A3)

This is a 3.7V, 800mAh (2.96Wh) Li-ion cell built to the HB4A3 specification. It fits the Huawei G6620, T1201, T1209, and G7210 handsets. If your original cell is swelling, refusing to charge, or dropping voltage under screen and modem load, this is the direct swap.

• G6620 / T1201 / T1209 / G7210 compatibility: All four models use the same HB4A3 cell format — identical footprint at 53 × 34 × 4.80mm, same 3.7V nominal rail, and the same three-contact connector layout. One cell covers the full group.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the G6620 platform. The BMS accepted the charge IC handshake cleanly, protection circuitry tripped correctly at the low-voltage cutoff, and the cell held stable voltage under simultaneous screen and modem draw.
• Fuel gauge recalibration on first use: On first install, disable any fast-charge or power-saving override and run one full discharge-to-charge cycle at standard current. This gives the fuel gauge IC time to map the new cell's actual discharge curve before high-current charging pushes current into an uncalibrated state.

Sudden shutdown at 20–30% on the HB4A3 replacement cell

This is the most common complaint after fitting a new cell into the G6620 series. The fuel gauge IC still holds calibration data from the original, degraded cell — so it miscalculates remaining capacity relative to the new cell's discharge curve. When the modem transmits or the screen peaks brightness, actual cell voltage drops faster than the gauge predicts. The phone's protection circuit sees the voltage cliff first and shuts down before the gauge reaches 0%. One full uninterrupted discharge cycle, letting the phone power off on its own and then charging back to 100% without interruption, resets the coulomb counter to match the new cell.

Phone reports wrong battery percentage after the cell swap

After replacing the HB4A3, the OS percentage display often reads high or low by 10–20% for the first few charge cycles. The fuel gauge IC on these Huawei models uses a learned discharge curve stored from the previous cell — that data does not auto-clear on swap. The fix is straightforward: drain the phone to automatic shutdown, then charge uninterrupted to 100% without removing the charger. After two to three full cycles done this way, the coulomb counter recalibrates and percentage accuracy returns to normal.