I just bought 500va UPS battery backup for my home system. I was thinking how great it would be to have this thing connected to my inverter in my car and then have my wx-worx, ATI TV system and my laptop on it. My laptop is of course all ready battery backed up internally but the other systems aren't. It would be nice to turn off my car engine, have everything still running (for up to 20 minutes?) and not have it drain my car battery. Has anyone else had any luck chasing with a UPS?