Sorry that i gave bad advice. There used to be a power save mode though. This is from the flash update instruction in the old forum:"On a James Tyler Variax guitar, ensure that the Volume knob on the guitar is NOT set to the '0' position as it will put the guitar into Power Save Mode. Make sure that the Volume knob is set higher than 0 when updating or editing the JTV guitar."
If you move the volume to 0 it will go to sleep after a few minutes. RTFM ;-)