I have a 2007 Vantage and for the third time I have had to replace the battery. The battery is always on a battery maintainer, however a week ago I disconnected the battery maintainer and the battery voltage dropped to 9 volts. Charging the battery overnight made no difference. This battery was replaced in April 2021 by the dealer.
I decided to replace this battery with an AGM Duracell, available from my local Sams Club. The old battery was an Interstate T8 Ah 90. The new battery is an Duracell AGM H8 CCA 850 92Ah.
Pics below




The battery clamps (Red arrows) have been narrowed 1 inch each to facilitate removing them for battery replacement.
If you are interested in the clamp modification or the battery removal process, please PM me for the website address.

 

I too have a Sam's Duracell. No Problems.
FWIW- Some batteries have a tendency to build/hold a memory. For that reason I will leave the car off the maintainer from time to time for a week or so to allow the battery to drain off a little. Fortunately here in Florida we have more drive months than our Northern friends. Of course the excuse to drive the car....is to charge the battery, right.

 

I do the same, when I can anticipate that I will be driving the Aston in a day or so, I just pull it off the tender . . . Seems to work for cars in the past, though the Aston is quite particular

 

This sounds familiar.

I found a problem with my Vantage that was causing a lot of electrical issues, including an apparent battery drain. You might want to check what I found to see if you have the same condition.

Put the car on a lift or jack stands. You'll see that the right front inner fender liner extends rearward along the bottom of the car. Remove the Torx bolts that hold the aft-most section on. Above it, you'll see a stud with two cable terminals on it (see photo below). This is where the positive cable from the alternator connects to the positive cable to the battery. In my case, the nut that holds them on the stud had vibrated itself loose and fallen off at some point, and those two cable terminals were barely touching each other, certainly not enough to adequately charge the battery while driving.

After putting a new washer and nut on that stud I never had any electrical issues again, and I found I could go 2-3 weeks between drives without a tender on, and the car started up just fine.

If you can find the post I made about this a couple years ago it has the size of the nut needed.

 

13mm nut, and on the top side is the other connection you want to check also. It's directly in from of the CEM (fuse box/control module) also for corrosion.

 

I have my charger on a timer, only coming on for a couple hours a day just so there is a condition of the current going both ways. I don't like the idea of constantly trying to force current into the battery.

 

I will add -

The way you are going through batteries I suggest there is some parasitic draw occurring somewhere in the car that has the battery being taxed all the time. Besides an obvious short to ground somewhere (that shouldn't happen w/o a fuse blowing somewhere), or poor/loose ground or +12v, something could be running constantly and not shutting down.

Often these come from aftermarket accessories, things like:
Stereo aftermarket products
Radar detectors,
Phone chargers,
ETC.,
Check anything in the car like that, make sure it is shutting down after ignition off. Once in a great while, I've seen actual factory accessories that should shut down, stay running and until addressed, kills batteries.

Referencing post #4, this is very coincidental, but I had the right front wheel well opened on my 2018 DB11 V12 and the same high voltage positive "lug" exists there too, where the positive battery cable connects. Funny thing, I was in there to change out the passenger's door compression cylinder, saw that terminal and instinctively checked its tightness. Good advice!

 

I can see that with a charger and good that you monitor it that way.

This is the reason why I use a battery maintainer and not a charger, because a good maintainer essentially toggles itself through the recharge cycles then reaches a point where it monitors battery condition then automatically switches back on when the battery needs it. Here I am talking about my car possibly sitting on a maintainer for a number of weeks unmonitored.

My goto maintainer is the CTEK BC I like they separate lead flood acid charging from AGM, or Lithium.

I have both the MXS 5.0 and a 7002. I've used both on my DB11 and either handles that AGM battery well.

This is the 5.0 and has a more illustrative monitor on the unit than the 7002 does and it uses 8 stages of maintaining.

 

I don't think I have a battery drain. I can go weeks without the battery maintainer and the battery stays charged. I have decided not to keep the battery on the battery maintainer all the time when the car is not being driven. In addition, I am going to change the maintainer to a CTEK. Its overpriced but has a good reputation.

 

this is great to know. I will check this next time I have my car on the lift...

 

Happy to help.

 

I'm so new I don't even have my car yet (2012 V8V S to be picked up 9/28), but let me put in a plug for Odyssey AGM batteries. My former hobby was amateur (SCCA) sports car racing, and I used Odyssey batteries for many, many years, getting 5 or 6 years typically. Everyone in my class runs total loss ignition/electrics (i.e. no on-board charging), so the batteries get worked pretty hard. I've also had Odyssey batteries in my turbo Miata, where they lasted even longer. I would only change brands for a lithium battery at this point.

 

there are lightweight lithium options for our cars