O2 XDA Flint Replacement Battery 3.7V 2000mAh ATHE160

O2 XDA Flint — 3.7V Li-ion Replacement Battery (ATHE160)

This is a 3.7V 2000mAh Li-ion replacement battery for the O2 XDA Flint Windows Mobile smartphone. It replaces OEM part numbers ATHE160 and 35H00081-00M. The cell fits the original battery bay with no modification required.

• XDA Flint platform fit: The XDA Flint uses a single-cell Li-ion pack at 3.7V nominal. The connector pinout and BMS handshake protocol on this replacement match the original charge IC expectations, so the device accepts charge cycles without throwing fault states.
• Bench tested on actual hardware: We cycled this cell through charge and full discharge on the XDA Flint platform. The BMS held voltage above 3.0V through the discharge curve and did not trigger early cutoff under simulated screen and radio load.
• Fuel gauge recalibration on first use: After fitting this cell, run one complete discharge down to automatic shutdown, then charge uninterrupted to 100% before normal use. The XDA Flint's fuel gauge IC reads the new cell's discharge curve during this cycle and stops reporting leftover calibration data from the old cell.

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

This happens because the fuel gauge IC is still calibrated to the old cell's discharge curve. The new cell hits a voltage cliff under screen or radio load at a point the IC did not predict. The device reads 25% but the cell voltage has already dropped below the cutoff threshold the charge IC is watching. One full discharge-to-shutdown followed by an uninterrupted charge cycle resets the coulomb counter and resolves this.

XDA Flint not powering on after the replacement battery sat in storage

Li-ion cells self-discharge in storage. If the cell dropped below approximately 2.5V, the BMS enters lockout to prevent damage and the phone will not power on or show a charging indicator. Connect the device to a low-current USB source and leave it for 20–30 minutes without pressing the power button. Most BMS circuits begin trickle recovery at this point and the device will show a charge screen once cell voltage climbs back above 2.8V.