O2 XDA Flame XP-08 Replacement Battery 3.7V 3150mAh

O2 XDA Flame — 3.7V Li-Polymer Replacement Battery (XP-08)

This is a 3.7V, 3150mAh lithium-polymer cell built to fit the O2 XDA Flame PDA-phone. It replaces OEM part XP-08, which is the original battery used in this Windows Mobile device. Voltage, connector pinout, and physical dimensions match the XDA Flame battery bay exactly.

• XDA Flame battery platform: The XDA Flame uses a single-cell Li-Polymer pack at 3.7V nominal, with a low-profile form factor specific to its compact chassis. No other XDA variant shares this exact cell geometry, so fitment is model-specific.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the XDA Flame hardware. The BMS accepted charge handshake correctly and held voltage above 3.5V under sustained screen and radio load without triggering early cutoff.
• Fuel gauge recalibration on first use: After installing this cell, run one complete discharge down to automatic shutdown, then charge uninterrupted to 100% before resuming normal use. The XDA Flame's fuel gauge IC was calibrated to the original cell's discharge curve — skipping this step will cause the percentage readout to drift significantly against the new cell.

Sudden shutdown at 20–30% on the XDA Flame after a cell swap

This is a voltage cliff issue, not a capacity defect. The XDA Flame's modem and display draw a combined current spike that a freshly installed, uncalibrated cell cannot sustain at lower state-of-charge. The cell voltage drops briefly below the BMS cutoff threshold — around 3.0V — triggering an immediate shutdown even though the fuel gauge still reads charge remaining. One full discharge-charge cycle recalibrates the coulomb counter and the shutdown behaviour corrects itself.

XDA Flame showing erratic or jumping battery percentage after replacement

The fuel gauge IC on the XDA Flame stores a learned discharge curve from the original XP-08 cell. A new cell with a slightly different internal impedance profile causes the IC to misread state-of-charge, producing percentage jumps of 10–15% in either direction. This is not a fault with the replacement cell. Discharge the device fully until it powers off automatically, then charge to 100% in one uninterrupted session — this forces the IC to write a new reference curve. After that cycle, percentage reporting stabilises.