I bought a new 2011 edge and had the same problem everyone else is having. It has ford sync with backup camera. I think this is where the problems come in, to much draw maintaining the computer even with key off. Anyhow I took it to the ford garage and they said they would install a battery tender, when they got done (took them 4 hrs) they tried to charge me $160 I said no way the manual says it will work so fix it so it will work they relented and charged me nothing. The first time I hooked it up to tow, blew the fuses in the motor home for the stoplight . I knew it had worked right before they had worked on it so when I got to where I was going took a look at it they had hooked the ground wire from the battery to the brake light terminal in the plug. So I switched it to the ground terminal and it has worked fine since. Took me about 15 minutes to rewire. I should have done it in the first place but thought it was their problem they should fix it. Lithia Ford in Boise, Idaho. This is my first Ford in 30 years and will be my last.