Sansa Fuze (v2) FLAC battery life

[Spandexninja]

I bought a 'new' Sansa fuze v2 from the Sandisk store and it lasts about 9 hours playing flac at 1/4 volume with the latest firmware. How much will this increase if I switch to rockbox?

Also, do rockbox themes have any effect on battery life outside of how bright the theme is?

I would test it myself but I don't want to break warranty if there isn't a decent (2+ hours) increase.

[saratoga]

Battery life for flac in rockbox is about double the sandisk firmware.

[Carson Dyle]

A related question:

What about battery life in Rockbox playing FLAC vs Mp3? I imagine Mp3 must use more CPU resources, but would be read much quicker from memory or card.

[saratoga]

I never tested it, but there are some tests here with flac and its very similar to MP3:

http://www.rockbox.org/wiki/SansaRuntime