About this replacement
Wiko U Feel / U Feel Lite Series — 3.8V Li-Polymer Replacement Battery (S104-U76000-002)
This is a 3.8V, 2400mAh (9.12Wh) lithium-polymer cell that replaces the original battery in the Wiko U Feel, U Feel Lite, U Feel Lite 4G, and P5601. It fits where the original cell sits and uses the same connector and BMS communication lines. Swap it in when the phone drops off charge fast, shuts down unexpectedly, or no longer powers on.
- U Feel and U Feel Lite platform fit: The U Feel and U Feel Lite variants share the same battery bay dimensions, connector pinout, and 3.8V voltage rail. One cell covers the full range because the fuel gauge IC and charge controller speak the same protocol across these models.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the U Feel platform. The BMS accepted charge from the phone's charge IC without triggering an over-voltage cutoff, and the fuel gauge IC tracked state-of-charge through each cycle without jumping erratically.
- Fuel gauge recalibration on first use: After installation, disable fast charging and complete one full discharge-to-charge cycle before resuming normal use. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell — skipping this step causes the percentage readout to be unreliable for the first several days.
Sudden shutdown at 20–30% on the U Feel after a cell swap
The U Feel's fuel gauge IC stores a learned discharge curve from the old cell. When a new cell goes in, that stored curve no longer matches the actual voltage-versus-capacity profile. Under modem or display load, the phone sees a voltage drop it doesn't expect and interprets it as a critically low cell — triggering a protective shutdown even though charge remains. One full discharge cycle down to automatic cutoff, followed by a full charge to 100%, forces the coulomb counter to reset its endpoints against the new cell. After that cycle, the reported percentage tracks correctly under load.
Device not powering on after the battery sat in storage
A lithium-polymer cell that self-discharges below approximately 2.5V per cell triggers BMS lockout — the protection circuit cuts output to prevent cell damage, and the phone cannot draw enough current to boot. Plug in a known-working USB charger and leave it connected for 15–20 minutes without attempting to power on. The charge IC on the phone trickle-charges the cell back above the BMS re-enable threshold, typically around 2.9V, at which point the protection circuit releases and normal charging resumes.