2005 Dodge Grand Caravan cuts off while driving

I have a 2005 Dodge Grand Caravan that is having multiple electrical issues. The problem first starts to show with the instrument panel needles going all the way to the right and coming back to the left. Some of the instrument lights stay lit. Then either in the next few minutes or days, the engine will shut off while driving. I can wait 30 seconds and sometimes it will start. After this sequence occurs, when I turn the key, the instrument lights will come on for a millisecond and then the engine will not start at all.
I take it into the dealer and they say that the battery is severely discharged. They charge up the battery and the problem goes away for 1500-3000 miles. Of course, the dealer does not know what is causing the problem.

It seems like one of the issues could be a defective ignition switch, but what I can’t figure out is what is causing the battery to severely discharge?
I have removed the BMC fuse, waited 30 seconds and this would allow the vehicle to start, but I have stopped trying this approach because it does not remedy the situation long term.

See:

http://community.cartalk.com/search?cx=partner-pub-7133054861616181%3A2yk2yg-lkla&cof=FORID%3A11&ie=ISO-8859-1&q=battery+drain&sa=Search