Apple iPOD 1st Generation Replacement Battery 3.7V 1600mAh

Apple iPod 1st & 2nd Generation — 3.7V Li-Polymer Replacement Battery (P325385A4H)

This 3.7V 1600mAh lithium-polymer battery replaces the original cell in Apple iPod 1st and 2nd generation media players. It matches the OEM part number P325385A4H and fits the slim internal cavity at 84.90 × 54.69 × 4.00mm. If your iPod no longer holds a charge or won't power on, this cell is the direct hardware fix.

• iPod 1st and 2nd generation compatibility: Both generations share the same 3.7V battery bay, connector pinout, and charge management circuit. One cell covers both without modification.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on a 1st gen iPod. The BMS accepted charge current normally, held cell voltage above 3.5V through the majority of the cycle, and triggered low-voltage cutoff cleanly without hanging the firmware.
• Post-swap charge cycle on iPod hardware: After fitting a new cell, connect the iPod to its original FireWire or USB charger and leave it for a full uninterrupted charge before first use. Swapping cells resets the charge controller's internal state — starting with a complete cycle lets the chip re-establish accurate voltage reference points for the battery indicator.

Battery percentage jumping erratically after cell swap

The iPod's fuel gauge reads battery state by tracking voltage thresholds — it does not count charge cycles the way modern smartphones do. When a new cell goes in, the controller still holds the old voltage map from the depleted original battery. This mismatch causes the percentage display to jump — often from 80% to 20% in seconds, or to report full when the cell is half charged. Running two or three complete charge and discharge cycles forces the controller to re-map its thresholds against the new cell's actual voltage curve. After that, the indicator stabilises.

Playback cutting out before the battery indicator reads empty

At the tail end of a lithium-polymer discharge, cell voltage drops steeply — from around 3.5V to the BMS cutoff at 3.0V within a short window. The iPod's audio amplifier draws a spike of current on every bass transient, and that spike can pull the voltage below the BMS trip threshold even when the display still shows a bar or two of battery remaining. The result is abrupt playback shutdown with charge still apparently left. If this happens consistently, the cell has likely aged past its usable capacity — a fresh 1600mAh cell restores the voltage buffer the amplifier needs. Confirm the new cell is fully charged to 4.2V before testing.