About this replacement
Wiko DuElle — 3.7V Li-ion Replacement Battery (Duelle)
This is a 3.7V, 900mAh Li-ion replacement battery for the Wiko DuElle smartphone. It fits directly into the DuElle handset and restores power to calling, messaging, and app functions. Capacity is 3.33Wh, matching the original cell specification.
- DuElle platform fit: The DuElle runs a single-cell Li-ion rail at 3.7V nominal. The connector pinout and BMS handshake on this cell match the original board layout, so the charge IC recognises the pack without error flags.
- Bench tested on actual hardware: We cycled this cell through charge and load on the DuElle board. The BMS accepted charge at the expected cut-off voltage and the fuel gauge IC tracked state-of-charge without tripping a fault.
- Fuel gauge recalibration on first use: On first use after installation, disable any fast-charge mode and run one 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 pushes current into an uncalibrated cell.
Why the DuElle reports wrong battery percentage after a cell swap
The DuElle's fuel gauge IC stores a learned discharge curve from the original cell. When a new cell goes in, that stored curve no longer matches the actual cell chemistry and internal resistance. The OS reads state-of-charge from the IC, not from the cell directly, so the percentage shown can be off by 10–20 points early on. One complete discharge down to device cut-off, followed by a full charge to 4.2V, forces the IC to relearn the curve against the new cell.
Sudden shutdown at 20–30% on the replacement cell
This happens when the modem or screen draws a current spike the cell cannot sustain without voltage dropping below the BMS protection threshold. The BMS sees the voltage cliff and cuts output before the OS has time to log a low-battery warning. It is not a faulty cell — it is the fuel gauge IC still using a stale capacity estimate. Run one full calibration cycle and check that the resting voltage after a full charge reads at or above 4.15V.