Microsoft Zune 30GB Replacement Battery 3.7V 700mAh

Microsoft Zune 30GB — 3.7V Li-ion Replacement Battery (G71C0006Z110)

This is a 3.7V, 700mAh Li-ion replacement cell for the Microsoft Zune 30GB portable media player. It fits the Zune 1089, 1090, and 1091 variants alongside the standard 30GB model. Swap it in when the original cell no longer holds charge or the player won't power on after sitting unused.

• Zune 30GB platform fit: The 1089, 1090, and 1091 model numbers are regional and retail variants of the same 30GB hardware. They share the same PCB layout, connector pinout, and battery cavity dimensions — one cell fits all four.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on a Zune 30GB unit. The BMS accepted charge current normally, voltage held above 3.5V through the majority of discharge, and the protection circuit tripped cleanly at the low-voltage threshold without locking up the board.
• Post-install charge cycle: After fitting a new cell, connect the Zune to its original charger and leave it for a full uninterrupted charge before first use. Cells that ship partially discharged can trigger the player's deep discharge protection state, which blocks normal boot until trickle charge raises the cell above the minimum threshold voltage.

Battery percentage jumping after a cell swap on the Zune 30GB

The Zune 30GB estimates charge level by reading cell voltage against a fixed lookup table stored in firmware. A new cell has a slightly different discharge curve than the aged original, so the percentage display recalibrates over the first few charge and discharge cycles. You may see the indicator jump from 80% to 40% or stall at 99% mid-charge. Run two to three full charge and discharge cycles and the reading will stabilise.

Playback cutting out before the battery indicator shows empty

The audio amplifier inside the Zune 30GB draws more current than the processor or display. Near the end of discharge, cell voltage sags under that load even though the firmware still reads the battery as partially full. When voltage drops below approximately 3.2V under load, the amplifier loses enough headroom to drop audio before the low-battery indicator triggers. If this happens, the fix is a full charge — do not attempt to squeeze more playback from a cell at that point, as repeated deep sag accelerates cell degradation.