Wiko KAR Replacement Battery 3.7V 1000mAh Li-ion

Wiko KAR / KaWa / FiJi Series — 3.7V Li-ion Replacement Battery (Kar, FiJi, KaWa)

This is a 3.7V, 1000mAh Li-ion cell for the Wiko KAR, KaWa, and FiJi smartphones. It replaces a degraded or failed original cell that can no longer hold a stable charge under normal phone load. Voltage and physical dimensions match OEM spec: 59.66 × 38.10 × 4.80mm.

• KAR, KaWa, and FiJi compatibility: All three models share the same 3.7V single-cell architecture, connector pinout, and battery bay dimensions — one cell fits all three without modification.
• Bench tested on actual hardware: We cycled this cell through charge and load on the bench. The BMS accepted the charge IC handshake cleanly and held voltage above the low-battery cutoff threshold under simulated screen and modem load.
• First-cycle fuel gauge recalibration: On first use after installation, disable fast charging and run one full discharge-to-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before reporting accurate percentages to the OS.

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

The Wiko KAR's fuel gauge IC stores a charge curve calibrated to the original cell. A new cell has a slightly different internal resistance profile, which means the IC underestimates remaining capacity at mid-range states of charge. When the modem or display draws a current spike, the cell voltage dips below the BMS cutoff threshold — even though the OS still shows 20–30%. One complete slow-charge cycle resets the coulomb counter and eliminates most of these false shutdowns.

Phone not powering on after the replacement cell sat in storage

Li-ion cells in extended storage self-discharge below 2.5V per cell. At that voltage, the BMS trips into lockout mode to prevent damage — the phone will not respond to the power button or show a charging indicator. Connect the phone to a low-current USB charger (500mA wall adapter, not a fast charger) and leave it for 20–30 minutes without pressing anything. Once the cell climbs above approximately 2.8V, the BMS releases and the phone will boot or show the charging screen.