Why Does My iPod Run Out of Battery So Fast?

During music playback, the backlight for the iPod's screen remains off. However, this is not the case when you watch videos, use applications or browse the Web on a Wi-Fi connection. The screen backlight requires significant battery power; constant screen usage reduces the battery life of the iPod classic from 36 to six hours, and reduces the battery life of the iPod Touch from 40 to seven hours.

The hard drive-based iPod classic has an internal memory chip that serves as a buffer for audio data. By filling the buffer with the data for the current and next few tracks, the iPod limits the amount of time that the hard drive is used. When you skip tracks, the iPod engages the hard drive to refill the buffer. If you do this frequently, you will find that the battery life of the iPod is significantly reduced from the 36 hour maximum.

All iPod batteries perform best in the temperature of an average air-conditioned room -- about 72 degrees Fahrenheit. Expect the battery life of any iPod model to be slightly reduced in temperatures that you would not find comfortable.

Most iPod models have the ability to play uncompressed audio in the WAV format and high-quality compressed audio in the Apple Lossless format. Both of these formats have very large file sizes compared to the common MP3 format. If you play an audio file that is larger than the iPod can store in the buffer, it is forced to transfer data from the hard drive more often, decreasing the life of the battery.

Apple estimates that a new iPod battery can be used and recharged as many as 400 times before the maximum capacity begins to decrease. If you charge your iPod daily and have owned it for more than one year, you may find that the battery no longer performs as well as it once did. Apple has a battery replacement service for iPods that are no longer covered under the original factory warranty. Depending on the model, Apple charges $49 to $79 for this service, as of 2011.