The Rockbox manual for my Sansa Clip Plus has the following section: Optimising battery runtime
Rockbox offers a lot of settings that have high impact on the battery runtime of your player. The largest power savings can be achieved through disabling unneeded hardware components for some of those there are settings available. Another area of savings is avoiding or reducing CPU boosting through disabling computing intense features (e.g. sound processing) or using effective audio codecs. The following provides a short overview of the most relevant settings and rules of thumb. I'd like to save power by "disabling unneeded hardware components". How do I do this?