Fitting DAB Radio

The 30 minute switch off is an annoying side issue which i have never experienced on any other vehicle radio.  I wish to fit a newer DAB radio which hopefully will not switch off after 30 minutes and has usb/ ipod/aux connections. I am aware of how fast the vehicle battery can be run flat by the radio, so the idea of hooking up to leisure battery is more preferable. The information provided so far has been very useful and wil need to be digested without wine.
thanks
MJ