About this replacement
Apple iPod 4th Generation / iPod Photo — 3.7V Li-ion Replacement Battery (616-0183)
This 3.7V 1200mAh Li-ion battery replaces the original cell in the Apple iPod 4th Generation and iPod Photo, including the 40GB M9585LL/A and M9585ZR/A models. It cross-references OEM part numbers 616-0183, 616-0206, 616-0215, AW4701218074, and ICP0534500. Install it when the original cell no longer holds enough charge to run playback.
- iPod 4th Gen and Photo compatibility: Both the standard 4th Generation and the Photo variants share the same 3.7V single-cell architecture, connector pinout, and BMS voltage thresholds — which is why one cell covers the entire range. The 51 × 36 × 7mm footprint sits flush in the bay without modification.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge runs on a 4th Gen unit. The BMS accepted the new cell without error, held the charge curve through a complete discharge, and did not trigger low-voltage cutoff prematurely.
- First charge after cell swap: After fitting this battery, connect the iPod to a charger before powering it on. Media players frequently enter deep-discharge protection after a cell swap, and skipping the initial charge can lock the device in a state where it won't respond to the hold switch or center button.
Battery percentage jumping erratically after cell swap
The iPod's fuel gauge is calibrated against the charge curve of the original cell. A new cell has a slightly different internal resistance profile, so the voltage-threshold indicator takes several full cycles to recalibrate. You'll see the percentage jump — sometimes dropping 20% in seconds — during the first two or three charge cycles. Run two full charge-to-depletion cycles and the readout stabilises. If it still jumps after three cycles, check that the battery connector is fully seated.
Playback cutting out before the battery indicator shows empty
The iPod's audio amplifier draws a short current spike when the cell voltage drops toward the lower end of its discharge curve. If the cell is aged or the connector has resistance from corrosion, that spike causes the voltage to sag below the BMS cutoff threshold — killing playback even though the indicator still shows remaining charge. Clean the battery connector pads with isopropyl alcohol, reseat the connector, and check the cell voltage with a meter. A resting voltage below 3.5V means the cell needs replacing; 3.7V at rest is the target after a full charge.