I-Mate Ultimate 9502 Replacement Battery 3.7V 1700mAh 303ATL0000A

I-Mate Ultimate 9502 — 3.7V Li-Polymer Replacement Battery (303ATL0000A)

This 3.7V, 1700mAh lithium-polymer battery is a direct cell replacement for the I-Mate Ultimate 9502 Windows Mobile PDA phone. It matches OEM part numbers 303ATL0000A and L017YS0100732, fitting the original battery bay without modification. Capacity data is sourced from the product specification — 6.29Wh total energy at nominal voltage.

• Ultimate 9502 platform fit: The 9502 uses a slim Li-Polymer pouch cell with specific dimensional tolerances — 74.20 × 46.50 × 5.20mm. Any deviation in thickness causes cover fitment issues or connector misalignment. This cell matches those tolerances and uses the same connector pinout as the OEM unit.
• Bench tested on actual hardware: We cycled this cell through charge and discharge while monitoring BMS cutoff behaviour. The protection circuit trips cleanly at the low-voltage threshold, and the charge IC accepted standard 4.2V CV/CC termination without error flags.
• Fuel gauge recalibration on first install: After fitting this cell, run one complete discharge to automatic shutoff, then charge uninterrupted to 100% before normal use. The Ultimate 9502's fuel gauge IC is calibrated to the old cell's discharge curve — skipping this step causes the OS to misread state-of-charge from the first power-on.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage cliff issue, not a capacity fault. When the modem transmits or the display brightness spikes, current draw pulls the cell voltage below the BMS cutoff threshold before the fuel gauge reads zero. A new cell with an uncalibrated coulomb counter makes this worse — the IC doesn't know the actual remaining energy. Run one full discharge-to-shutoff cycle, then a full charge, to give the fuel gauge IC a real baseline. After that cycle, shutdowns below 20% should stop unless the cell itself is damaged.

Device not powering on after the battery sat in storage

Li-Polymer cells that drop below approximately 2.5V per cell trigger BMS lockout — the protection circuit disconnects the cell to prevent damage from deep discharge. The 9502 will show no response to the power button and no charging indicator. Connect it to a wall charger, not a PC USB port, and leave it for 20–30 minutes without pressing anything. Most BMS circuits re-initialise once the charger pushes enough current to bring cell voltage back above the lockout threshold — typically around 2.9–3.0V — at which point the device will begin a normal charge cycle.