FYI:
Also this:
Tests find DRM shortens player battery life by up to ~25%:
When users take the specifications of an MP3 player into consideration, one very important factor most take into account is the rated battery life. However, as many are aware, the battery life stated is generally the runtime from a full charge in ideal conditions, such as when the player is left playing without any sound enhancements (EQ, bass-boost, etc.), volume set to a moderate level, all music is 128kbps MP3, backlit display goes out within a few seconds or off completely and so on. However, according to tests conducted, players met or exceeded their claims, however, one feature that has a drastic affect on battery life is the infamous Digital Rights Management or DRM. Of all the current DRM types currently in use, Apple's FairPlay DRM seems to have less of an effect with battery life being reduced by around 8% when compared with MP3 playback. Windows DRM files reduce playback by up to 12%, which is not of any concern for IPOD owners, but of great concern for "Plays for Sure" device owners.
When it comes to maximising battery life in a portable MP3 player, this is a clear sign that one should avoid playing DRM protected music if at all possible and also another good reason to get the music converted into a more battery-friendly format. While 2 to 4 hours less play time may not seem a lot to some people, this can be the difference between listening to music to the end of a lengthy journey or getting left in silence a couple of hours before the journey is complete.
With the shorter battery life caused by DRM, this means that consumers have to recharge their battery more often, which in turn results in a shorter overall battery life before it needs replacement.
