O2 XDA Nova ELF0160 Replacement Battery 3.7V 2000mAh

O2 XDA Nova — 3.7V Li-ion Replacement Battery (ELF0160)

This is a 3.7V, 2000mAh Li-ion cell for the O2 XDA Nova — a Windows Mobile handheld smartphone from the mid-2000s. It replaces OEM part numbers ELF0160, 35H00095-00M, and FFEA175B009951. If your original cell no longer holds charge or the device shuts down unexpectedly, this cell restores the XDA Nova to working condition.

• XDA Nova platform fit: The XDA Nova uses a single-cell Li-ion pack running a 3.7V nominal rail. This cell matches that rail, the physical dimensions (50.84 × 36.65 × 10.78mm), and the connector pinout. The BMS communicates state-of-charge to the Windows Mobile power management layer through the same contact arrangement as the original pack.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge passes while monitoring BMS cutoff behaviour. The protection circuit tripped correctly at low-voltage floor, and the charge IC accepted the cell without fault flags during CC/CV transition.
• Fuel gauge recalibration on first cycle: On first use after fitting, run one complete discharge down to automatic cutoff, then charge fully without interruption. The XDA Nova's fuel gauge IC calibrates its coulomb counter against the new cell's discharge curve during this cycle — skipping it leads to inaccurate percentage readings for weeks.

Why the XDA Nova reports wrong battery percentage after a cell swap

The XDA Nova uses a fuel gauge IC that builds its state-of-charge model from the discharge curve of the cell it has seen previously. When a new cell goes in, the IC is still calibrated to the old cell's degraded curve. This mismatch causes the displayed percentage to read high, drop suddenly, or plateau for long periods. One full uninterrupted discharge-charge cycle forces the coulomb counter to remap against the new cell's actual capacity. After that cycle, percentage readings stabilise to within a few points of real state-of-charge.

Sudden shutdown at 20–30% on the XDA Nova

This happens when the cell voltage drops sharply under the combined load of the GSM radio, screen, and CPU — a voltage cliff specific to aged or deeply discharged cells. The BMS cuts output the moment cell voltage dips below roughly 3.0V under that combined draw, even though the resting voltage still reads higher. A replacement cell with full capacity holds voltage flat under the same load conditions and eliminates the cliff. If the shutdown persists on a new cell, check that the battery contacts are clean and making firm connection — a high-resistance contact causes the same voltage sag the BMS reads as a fault.