FWIW, I have a 2006 DB9 that lives in my garage. I have an inexpensive trickle charger from Black & Decker (BMB3). I attached a pigtail to power/ground in the engine bay. When I return to the garage I open the hood and plug it in. I leave the hood up to let the engine cool off. Once cool, I lower the hood. The electronics appreciate the hood being up, the battery likes the trickle charge...

 

I ended up buying the CTEK 5.0. Now I have a stupid question since I've never owned a car with the battery located under the rear seat. Please don't laugh at me, lol. The sales person told me that there were a couple of different ways to hook up a trickle charger, but I want to make sure I'm doing this correctly so I've attached a pic of the front engine bay. Is the best/easiest thing to do simply to attach the positive cable to the bolt located under the black "+" box & the negative to one of the frame bolts in the blue circle in the pic? And then after I plug in the CTEK, should I close the hood or just leave it up for the 3 weeks that we'll be gone? Again, sorry if this is a stupid question.

 

Positive to the post under the "+" lid -- squeeze the lid to release the catch. I clamp the negative cable to the alternator bracket. Don't know about the bolt you've circled -- might work.

I wouldn't trust the struts to hold the hood up for an extended period. I've had old ones give out after a couple of hours, sending the hood crashing down. I now use a short scrap of wood to block the hood latch and just rest the hood on it. Keeps it open a couple of inches, just enough to clear the positive clamp.

 

The bolt you circled has loc-tite on the threads and kinda stubborn to remove. There is 2 10mm headed bolts on the beam where your positive terminal is mounted to they have support brackets at an angle. That would keep your wire run to minium.

 

My thanks to both of you. Much appreciated..

 

It's actually super easy to get to the battery in the back seat. Takes less than 5 or 6 minutes to get to it and hook up the charger. I'm in NC for the summer and my car is back home in Indiana on the charger hooked directly to the battery as I type this. .

FWIW, YMMV