> How many? I've trialled mSATA, SDXC and Compact Flash. 16 hours is easily achievable using CF and a "fat" back that fits a 1900mah battery. Rockbox provides

> How many? I've trialled mSATA, SDXC and Compact Flash. 16 hours is easily achievable using CF and a "fat" back that fits a 1900mah battery. Rockbox provides a plugin called Battery Bench that allows you to benchmark how long you can continuously listen to music for. Having recently switched from mSATA to SDXC I am yet to run a benchmark for SD. From recent usage I would guess 12hrs is fairly easily achievable. EDIT: bwoodward has benched 60hrs of playback with a 5th gen Video and SDXC below.