Vodafone VPA Compact IV Replacement Battery 3.7V 2400mAh

Vodafone VPA Compact IV — 3.7V Li-Polymer Replacement Battery (35H00078-02M)

This 3.7V, 2400mAh Li-Polymer cell replaces the original battery in the Vodafone VPA Compact IV smartphone. It matches the OEM dimensions at 116.04 × 68.62 × 3.40mm and connects via the same flex-ribbon connector as the factory cell. Capacity is rated at 8.88Wh, matching what the VPA Compact IV's charge IC expects.

• VPA Compact IV fitment: The VPA Compact IV uses a fixed connector pinout and a charge IC tuned to a narrow voltage window. This cell sits within that window — 3.7V nominal, same as OEM — so the charge controller does not reject it on first contact.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on a VPA Compact IV unit. The BMS accepted charge without flagging an error, and cell voltage held stable across screen-on and modem-active load states.
• Fuel gauge recalibration on first use: After fitting, disable fast charging if available and run one full discharge-to-charge cycle before normal use. The fuel gauge IC on the VPA Compact IV is calibrated to the old cell's discharge curve — one full cycle lets it remap against the new cell and report accurate percentages.

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

This happens because the fuel gauge IC still holds the discharge curve of the old, degraded cell. When the new cell hits a voltage point the old curve mapped to 20–30%, the phone interprets it as critically low and shuts down — even though the cell has capacity left. The fix is a full calibration cycle: drain the phone until it shuts itself off, then charge uninterrupted to 100%. After one complete cycle, the coulomb counter resets its endpoints against the new cell, and premature shutdowns stop.

Phone not powering on after the replacement cell sat in storage

Li-Polymer cells self-discharge during storage. If the cell voltage dropped below 2.5V per cell, the BMS enters lockout mode to prevent damage — and the phone will not respond to the power button. Connect the phone to a wall charger, not a USB port, and leave it for 20–30 minutes without attempting to power on. Most BMS units on this platform will accept a trickle recovery charge once the cell climbs above 2.7V and will release the lockout automatically at that point.