Vodafone VPA Compact II WIZA16 Replacement Battery 3.7V 2800mAh

Vodafone VPA Compact II — 3.7V Li-ion Replacement Battery (WIZA16)

This is a 3.7V, 2800mAh Li-ion cell built to replace the original WIZA16 battery in the Vodafone VPA Compact II smartphone. It fits the VPA Compact II directly and restores mobile operation when the original cell has degraded or failed to hold charge. Capacity is 2800mAh — confirm this matches what you need before ordering.

• VPA Compact II fitment: The VPA Compact II uses a removable single-cell Li-ion pack at 3.7V nominal. The WIZA16 connector pinout carries the thermistor line that the charge IC reads during charging — a cell without this line will trigger a thermal fault and stop the charge cycle early.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the bench, monitoring BMS handshake, thermistor response, and charge IC acceptance. The cell passed thermal cutoff thresholds and completed full charge cycles without fault flags.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one full discharge-to-charge cycle before resuming normal charging. This gives the fuel gauge IC time to map the new cell's discharge curve — skipping this step is the main reason a new cell reports inaccurate percentages from day one.

Sudden shutdown at 20–30% on the VPA Compact II after a cell swap

The VPA Compact II fuel gauge IC stores a learned discharge curve from the previous cell. When a new cell goes in, that stored curve no longer matches actual cell voltage under load — particularly during screen-on or modem bursts. At around 20–30% reported charge, the real cell voltage can drop below the 3.4V minimum the phone requires under those loads, triggering an immediate shutdown even though the gauge still shows charge remaining. Running one complete discharge down to automatic shutdown, then a full uninterrupted charge, forces the coulomb counter to reset against the new cell's actual curve. After that cycle, the reported percentage will track real capacity accurately.

VPA Compact II feels warm near the battery compartment on first charge

A new Li-ion cell typically arrives with higher internal impedance than a cell that has been cycled. The charge IC on the VPA Compact II pushes current into that higher-impedance cell and more energy converts to heat than usual on the first charge. This is normal and settles after two or three full cycles as internal impedance drops. If warmth persists past three cycles or the phone becomes hot to the touch, check that the battery contacts are clean and seated flat — a misaligned contact raises resistance at the connector and keeps impedance elevated.