From my post on 11/19/2012:
My Garmin rugged mount is wired directly to the battery. When my bike's ignition is switched off with the key, the rugged mount is still powered.
I measured 8 ma draw from the rugged mount when my Montana is in the rugged mount and is turned off and my bike's ignition is switched off.
I measured no draw from the rugged mount when my Montana was removed from the rugged mount.
I use non-rechargeable lithium AA batteries in my Montana for those rare instances when I want to use my Montana and it is not in the rugged mount nor connected to my iMac.
Others do not detect this parasitic draw....