[dcarrb]

There are too many variables to say. I've left a door ajar overnight and found just the silly dome light drained the battery, but did the same thing with my silver SVX recently and it cranked right up. Never had a hint of trouble from the battery that came in my teal SVX 'til one day at a gas pump: Turned the key to leave and it didn't even have enough juice to click (and it was indeed the battery, not a starter relay thing).

Anything that rotates or generates heat will draw much more power than something solid-state, such as the radio. I'd be reluctant to sit for more than a couple of minutes with the blower running. And this rationale may be outdated, for all I know, but I too think it's not a good idea to sit with the switch ON without the engine running any longer than absolutely necessary.

dcb