About this replacement
Wiko Power U20 / U30 — 3.85V Li-Polymer Replacement Battery (4867A2)
This is a 3.85V, 5800mAh Li-Polymer cell replacing OEM part 4867A2 in the Wiko Power U20 and Power U30 smartphones. It fits both models because they share the same battery bay dimensions, connector pinout, and BMS communication protocol. Capacity matches OEM spec at 22.33Wh.
- Power U20 and U30 compatibility: Both handsets run the same battery bay at 103.90 × 66.70 × 4.60mm with an identical connector and BMS handshake line. One cell fits both without modification.
- Bench tested on actual hardware: We cycled this cell through full discharge and charge sequences on compatible hardware. The BMS accepted charge current correctly, the protection circuit tripped at the expected low-voltage threshold, and coulomb counting resumed normally after the first complete cycle.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging begins. Skipping this step often causes the OS to report incorrect percentages for the first several cycles.
Sudden shutdown at 20–30% on the Power U20 after a cell swap
The Wiko Power U20's fuel gauge IC retains the discharge curve of the old, degraded cell in memory. When a new cell is installed, the IC misreads the voltage profile and triggers a low-battery shutdown well before the cell is actually depleted. This is a calibration mismatch, not a fault in the replacement cell. Run one full discharge to automatic shutdown followed by a full charge to 100% with fast charging disabled — the fuel gauge IC resets its learned curve against the new cell's actual voltage floor, and shutdowns at false percentages stop.
USB fast charge not engaging on the first cycle after replacement
On the first charge cycle after a cell swap, the Power U20's charge IC may negotiate only standard 5V charging rather than its faster protocol. This happens because the new BMS starts with a conservative charge-acceptance state until it has completed one full cycle and confirmed cell health. Do not force a fast-charge adapter on the first cycle. Charge once at standard rate to 100%, then disconnect — fast charging will engage normally on the next charge session once the BMS has cleared its initial safety hold.