About this replacement
O2 Xda Stealth — 3.7V Li-Polymer Replacement Battery (XP-04)
This is a 3.7V 1400mAh Li-Polymer battery for the O2 Xda Stealth pocket PC. It replaces part numbers XP-04 and A2K40-STE090-ZOR. If your Xda Stealth no longer holds charge through a working day, this cell restores full operating capacity to the device.
- Xda Stealth platform fit: The Xda Stealth uses a Li-Polymer cell with a specific connector orientation and BMS handshake tied to the 3.7V nominal rail. This replacement matches that voltage profile and connector pinout, so the device firmware recognises the cell without errors.
- Bench tested on actual hardware: We cycled this battery through charge and discharge on the Xda Stealth platform and confirmed the BMS communicates correctly with the device, holds charge without premature cutoff, and reports state-of-charge accurately to the Windows Mobile battery indicator.
- Data sync before battery removal: The Xda Stealth holds open application state and unsaved files in SRAM, which is powered directly by the main battery. Before pulling the old cell, sync the device fully to your host PC via ActiveSync to avoid losing data, calendar entries, or open documents.
Why the Xda Stealth shows a low battery warning immediately after a new cell is fitted
A freshly shipped Li-Polymer cell arrives at partial state of charge — typically 40–60% — to meet transport safety requirements. The Xda Stealth reads this as a low battery condition and may warn or throttle performance before the first full charge cycle is complete. Connect the device to the charger before attempting to boot or use it. Once it reaches 4.2V at the cell terminals and the charge indicator clears, the battery indicator will report correctly.
Xda Stealth not booting after battery replacement
The Xda Stealth boot sequence requires a minimum voltage threshold at the battery terminals before the processor will initialise. If the replacement cell was too depleted on arrival, the device may show nothing on screen or flash briefly and shut down. Do not assume the battery is faulty — charge it for at least 30 minutes before the first boot attempt. If the device still will not start after a full charge, hold the hardware reset pin with a stylus to clear any corrupt boot state before powering on again.