Microsoft Zune 80gb/120gb 2nd Gen Replacement Battery Is This The Part I Need? -Improve Zune 80gb/120gb battery life-Potentially fix Zune 80gb/120gb not powering upIf your Zune 80gb/120gb battery life has diminished and is no longer holding a charge like it did, it's time to replace your Zune's battery. Replacing the battery can also be necessary in certain situations where the battery has failed completely and the device will not power up or continuously flashes the low battery screen. This new replacement battery for the Zune 80gb/120gb has a 850mAh charge capacity (OEM is only 660mAh) with a battery life anticipated at 30 hours of usage. Note that each individual users settings and usage will determine the actual battery life. The LCD on-time and WiFi usage will consume the most power.