Apple iPod Touch 5 Replacement Battery 3.7V 1000mAh 616-0621

Apple iPod Touch 5th Generation — 3.7V Li-Polymer Replacement Battery (616-0621)

This 3.7V 1000mAh Li-Polymer battery replaces the original cell in the Apple iPod Touch 5 and iPod Touch 5th Generation. It fits the compact media player that handles audio and video playback, app use, and Wi-Fi browsing. Capacity is 1000mAh (3.7Wh), matching the OEM specification.

• iPod Touch 5 and 5th Generation fit: Both model names reference the same hardware revision. They share an identical connector, cell footprint at 69.43 × 49.38 × 2.40mm, and the same BMS voltage thresholds — so one cell covers both.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on an iPod Touch 5 unit. The BMS accepted the cell without fault flags, cut off cleanly at the low-voltage threshold, and reported state-of-charge accurately across the full discharge curve.
• First-charge protocol after a cell swap: After fitting this battery, connect the device to a charger before attempting to power it on. Media players frequently enter a deep-discharge protection state after extended storage, and the BMS requires a slow trickle current before it will allow a normal charge rate or boot sequence.

Battery percentage jumping around after a cell swap

The iPod Touch 5 estimates state-of-charge by reading the cell's voltage against a fixed lookup table. A fresh cell has different internal resistance than the aged one it replaced, so the voltage curve doesn't match what the firmware expects. The indicator will read erratically — jumping several percent in either direction — until the firmware recalibrates. Run two full charge and discharge cycles without interruption and the percentage readout will stabilise.

Playback cutting out before the battery indicator reaches empty

The audio amplifier in the iPod Touch 5 is one of the higher-draw components in the device. As the cell approaches the bottom of its discharge curve, internal resistance rises and voltage sags under the amplifier's load — enough to trip the BMS undervoltage cutoff even when the indicator still shows charge remaining. This isn't a faulty cell; it's the BMS protecting the cell from over-discharge under real load. To confirm, check the battery percentage when cutout occurs — if it consistently happens above 5%, run a full discharge cycle to let the firmware reset its voltage-threshold calibration.