WINNER WG7 Replacement Battery 3.7V 900mAh Li-ion

WINNER WG7 — 3.7V Li-ion Replacement Battery

This is a 3.7V, 900mAh Li-ion cell for the WINNER WG7 smartphone. It slots in where the original battery sits and restores power to the device. Dimensions are 46.47 × 39.79 × 5.33mm — measure your original before ordering if unsure.

• WG7 platform fit: The WG7 runs a single-cell 3.7V nominal rail. This cell matches that voltage requirement and uses the same connector pinout as the factory unit, so the phone's charge IC sees a valid cell from the first boot.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the bench. The BMS held cutoff correctly at both ends — no overcharge trip, no premature low-voltage lockout at the floor.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging if the option is available, then run one complete discharge-charge cycle. This gives the fuel gauge IC a clean reference against the new cell's discharge curve before the charge IC pushes higher current into an uncalibrated cell.

Why the WG7 reports wrong battery percentage after a cell swap

The WG7's fuel gauge IC learns the discharge curve of whichever cell is installed. When you swap to a new cell, that learned curve no longer matches reality. The IC may read 40% and report 70%, or the reverse. One full discharge-charge cycle — down to automatic shutdown, then a full charge — gives the coulomb counter enough data to rebuild an accurate state-of-charge map. Until that cycle completes, percentage readings will be approximate.

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

A fresh Li-ion cell has higher internal impedance than a broken-in cell. When the WG7 pulls a burst of current — modem transmit, screen at full brightness, background sync — voltage sags sharply. If it sags below the BMS cutoff threshold, the phone shuts off even though the reported percentage still looks healthy. This is a voltage cliff caused by impedance, not a faulty cell. It typically resolves after 3–5 full charge cycles as the cell's impedance settles. If shutdowns persist past cycle 5, check that the battery connector is fully seated — a partial connection raises effective resistance further.