The Amazing Dead Battery!!! Help!

I HAVE A 1997 EXPEDITION EB 4WD, AND SINCE JULY 05 I SEEM TO HAVE A RECURRING PROBLEM. SOMETHING KEEPS KILLING THE BATTERY. I HAVE HAD 3 NEW BATTERIES, NEW CONNECTORS ON THE CABLE, AND JUST YESTERDAY A NEW MAIN BATTERY CABLE. ALT SEEMS TO BE CHARGING FINE, STARTER? SOMETIMES THE THING WON'T START AFTER 10 HOURS SOMETIMES IT WON'T START AFTER 2 HOURS. SINCE THIS HAS BEEN SUCH A PROBLEM MY HUSBAND STARTS THE TRUCK(with no problem) IN THE AM BEFORE HE LEAVES (6:00) AND TWO TIMES THIS WEEK (INCLUDING TODAY) WHEN I GET IN IT AT 8:00, IT IS JUST AS dead as if I had no battery in it at all. THE STRANGE PART IS, THAT IT WILL START WITH NO PROBLEM AS SOON AS YOU HOOK JUMPERS AND ANOTHER BATTERY UP TO IT-EVERY TIME! ANY IDEAS OUT THERE? THIS THING IS DRIVING ME CRAZY! LOCAL FORD DEALERSHIP HAS NO IDEA. WHAT COULD BE DRAINING ALL OF THE POWER IN THAT SHORT OF AN AMOUNT OF TIME???

This sounds like a bad ground. Trace the negative battery cable from the battery to where it grounds to the vehicle.
Gorillaweld