DOOV G25 Replacement Battery 3.7V 1650mAh BL-G25

DOOV G25 / D770 / D3 — 3.7V Li-ion Replacement Battery (BL-G25)

This is a 3.7V, 1650mAh Li-ion replacement cell for the DOOV G25, D770, and D3 smartphones. It replaces part number BL-G25 and fits the original battery bay without modification. Capacity is 1650mAh (6.11Wh), matching the factory specification.

• G25, D770, and D3 compatibility: All three models share the same battery bay dimensions and BL-G25 connector pinout. The charge IC and BMS handshake protocol are identical across the range, so one cell covers all three without adapters or firmware differences.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the G25 platform. The BMS accepted the cell on first connection, charge termination triggered correctly at 4.2V, and the protection circuit tripped as expected under short-circuit simulation.
• Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging if your device supports it and run one full discharge-charge cycle. The fuel gauge IC is calibrated to the old cell's discharge curve — one complete cycle lets it recalibrate against the new cell before high-current charging begins.

Sudden shutdown at 20–30% on the DOOV G25 after a cell swap

This happens because the fuel gauge IC still holds the old cell's voltage-to-capacity curve in memory. When the modem transmits or the screen peaks, the new cell's voltage drops faster than the IC expects at that state of charge. The phone reads that voltage dip as a critical low and shuts down before the display reaches 0%. One full discharge to auto-off followed by an uninterrupted charge to 100% forces the coulomb counter to rebuild its curve against the new cell.

Phone reports wrong battery percentage after BL-G25 replacement

The fuel gauge IC on the G25 stores a learned discharge model tied to the original cell's internal resistance profile. A new cell has different impedance, so the IC misreads state of charge — percentage can jump, stall, or read high while the phone is actually near empty. This is not a fault in the replacement cell. Drain the phone fully until it powers off, then charge uninterrupted to 100% without removing the cable — after one complete cycle the IC recalibrates and percentage tracking stabilises.