Wiko LENNY Replacement Battery 3.7V 1800mAh Li-ion

Wiko LENNY — 3.7V Li-ion Replacement Battery (LENNY)

This 3.7V, 1800mAh Li-ion cell replaces the original battery in the Wiko LENNY smartphone (model B0386126). It restores power to a device that has lost capacity through normal cell degradation. Voltage and capacity match the original factory specification.

• Wiko LENNY and B0386126 fitment: Both model references share the same battery bay dimensions, connector pinout, and BMS communication protocol — one cell covers both. The 77.48 × 49.90 × 4.20 mm footprint seats without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the LENNY platform. The BMS accepted charge current correctly, voltage under load stayed stable, and the protection circuit tripped at expected thresholds — no false cutoffs during the test.
• Fuel gauge recalibration on first use: After fitting this cell, disable fast charging if the option is available, then run one complete discharge-to-charge cycle at standard current. The LENNY's fuel gauge IC was calibrated to the old cell's discharge curve — one full cycle lets it map the new cell before reporting accurate percentages.

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

This happens because the fuel gauge IC still holds the discharge curve of the original degraded cell. When the new cell's actual voltage drops under modem or screen load, it hits a point the old curve maps as "empty" — even though percentage shows 20–30%. The phone cuts power to protect the SoC. One full discharge-and-charge cycle forces the coulomb counter to relearn the new cell's voltage curve and clears the mismatch.

Wiko LENNY not powering on after sitting in storage

Li-ion cells self-discharge during storage. If the cell drops below roughly 2.5V per cell, the BMS enters lockout mode and blocks charge current to prevent plating on the anode. The phone will show no response to a charger. Connect to a USB charger and hold the power button for 10–15 seconds — some units recover from BMS lockout this way. If the screen remains dark after two minutes on charge, try a different cable and charger rated at 5V/1A to confirm the charge IC is receiving input voltage.