S4300AE Wiko Jimmy Replacement Battery 3.7V 1700mAh

Wiko Jimmy — 3.7V Li-ion Replacement Battery (S4300AE)

The S4300AE is a 3.7V, 1700mAh Li-ion cell that fits the Wiko Jimmy smartphone. It replaces the original battery when the existing cell can no longer hold adequate charge or causes unexpected shutdowns. Voltage and capacity match OEM spec exactly.

• Wiko Jimmy fit: The Jimmy uses a removable cell format with a specific connector orientation and BMS handshake tied to the S4300AE part number. A cell with mismatched BMS signalling will cause the OS to reject the charge IC handshake or report a battery error on boot.
• Bench tested on actual hardware: We cycled this cell through full discharge and charge sequences, confirming the BMS cutoff triggers correctly at low voltage and that the charge IC accepts the cell without fault flags during the first 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 its coulomb counter against the new cell's discharge curve before any high-current charging pushes current into an uncalibrated state.

Why the Wiko Jimmy shuts down suddenly at 20–30% after a cell swap

The Jimmy's fuel gauge IC stores a discharge curve calibrated to the old, degraded cell. When a new cell with a steeper voltage-capacity curve is installed, the IC underestimates remaining charge at mid-range percentages. Under modem or screen load, the new cell's terminal voltage drops faster than the IC predicts, tripping the low-voltage cutoff before the displayed percentage reaches zero. One full discharge-charge cycle without interruption resets the coulomb counter and realigns the IC to the new cell's curve.

Phone feels warm near the battery during first charge after replacement

A new Li-ion cell has higher internal impedance than a broken-in cell. During the first charge cycle, the charge IC applies its standard current profile against this elevated impedance, which generates more heat than normal until the cell conditions through one full cycle. This is expected behaviour and not a fault. If the phone remains warm past the second full charge cycle, check that the charge IC has not defaulted to a higher charge rate — drop to a 5V/1A charger and complete one more full cycle at that lower rate.