Wiko LENNY 2 Replacement Battery 3.7V 1800mAh 5030

Wiko LENNY 2 / Lenny 3 — 3.7V Li-ion Replacement Battery (5030)

This is a 3.7V, 1800mAh Li-ion cell built to fit the Wiko LENNY 2 and Lenny 3 smartphones. It replaces OEM part number 5030 and slots into the original battery bay using the same connector and physical footprint. Capacity is 1800mAh (6.66Wh) — taken from the product specification, not estimated.

• LENNY 2 and Lenny 3 compatibility: Both models run the same 3.7V battery rail, share the same connector pinout, and use the same physical cavity dimensions. One cell covers both devices without modification.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the LENNY 2 platform. The BMS accepted the cell, charge termination triggered correctly at 4.2V, and protection cutoff engaged cleanly at the low-voltage threshold.
• Fuel gauge recalibration on first cycle: After fitting this cell, run one full discharge down to auto-shutdown, then charge to 100% without interruption. The LENNY 2 fuel gauge IC calibrates its coulomb counter against a complete discharge curve — skipping this step causes the OS to report inaccurate percentages for days.

Sudden shutdown at 20–30% on the LENNY 2 after a cell swap

This happens because the fuel gauge IC still holds the discharge curve of the old, degraded cell. The new cell has a steeper voltage drop near depletion, and the phone hits the hardware low-voltage cutoff before the OS percentage reaches zero. The modem and screen together can pull enough current to collapse cell voltage below 3.2V in under a second — faster than the gauge can track. One complete discharge-to-shutdown followed by a full charge corrects the stored curve and stops the early cutoff.

Phone shows 100% immediately after charging begins on the replacement cell

A fresh high-impedance cell reads a resting voltage close to 4.0V straight out of packaging. The LENNY 2 fuel gauge maps that open-circuit voltage to a high state-of-charge estimate before any real charging current flows. The displayed percentage is not accurate — it reflects the resting voltage, not actual stored energy. Charge the phone to full, let it discharge naturally to shutdown, then charge again to 100% to anchor the gauge to real capacity endpoints.