Help, Ford Explore battery dies when flat towing

I went ahead and installed a battery disconnect so I don't have to jump it anymore. This remains a mystery to me. Appears either the manual is wrong or I have a weak battery. I suspect that the manual is wrong because regardless of the key position the dash lights on both sides of the speedometer remain on and it appears that is what drains the battery after four or five hours. This is very frustrating to me as this was the main reason I purchased this particular tow car.