About this replacement
Wiko Fizz — 3.7V Li-ion Replacement Battery (FIZZ)
This is a 3.7V, 1500mAh Li-ion replacement battery for the Wiko Fizz smartphone. It fits the Fizz directly and restores normal device operation when the original cell has degraded. Capacity is 5.55Wh — matching the stock specification.
- Wiko Fizz fit: The Fizz uses a compact removable cell on a 3.7V single-cell rail with a direct connector to the charge IC. This replacement matches that connector pinout and voltage tolerance so the BMS handshake completes on first boot.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge on the Fizz platform. The BMS accepted the cell without fault flags, and the fuel gauge IC initialised correctly after one complete discharge cycle.
- Fuel gauge recalibration on first use: After fitting this cell, disable fast charging for the first full discharge-to-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's discharge curve before high-current charging begins on an uncalibrated cell.
Sudden shutdown at 20–30% on the Wiko Fizz after a cell swap
This happens when the fuel gauge IC is still calibrated to the old cell's voltage curve. The new cell hits a steeper voltage drop under modem or screen load, and the system reads it as a critical low before the displayed percentage catches up. The phone shuts down to protect the cell even though the gauge shows charge remaining. One full discharge cycle — down to automatic cutoff, then a full charge — lets the coulomb counter recalibrate to the new cell's actual curve.
Percentage jumping erratically in the first two days after fitting
The fuel gauge IC on the Fizz uses a learned discharge model tied to the original cell's internal resistance profile. A new cell has a different impedance signature, so the IC oscillates between estimates until it builds enough cycle data. This is not a fault in the replacement cell — it is the gauge recalibrating. Complete two full discharge-charge cycles without interruption and the percentage readout stabilises. If jumping continues past three full cycles, check that the battery connector is fully seated and making clean contact on all pins.