Battery Dying - recommendations please

[mikey k]

My battery is only holding charge for 3-4 days now

I think I found the OEM Varta 90 ah fitment for ~£90

Two questions;
Any one recommend a supplier?
Any one tried the AGM "glass Matt" batteries?

[pilgrim7777]

You probably have an AGM battery in your Vantage already, however...

AGM (Absorption Glass Mat) sealed battery technology was originally developed in 1985 for military aircraft where power, weight, safety, and reliability were paramount considerations.
AGM battery technology has continued to develop and offer improvements over other sealed battery technologies. AGM technology has become the next step in the evolution of both starting and deep cycle sealed batteries for marine, RV, and aviation applications. This "next generation" technology delivers increased safety, performance, and service life over all other existing sealed battery types, including gel technology.
In AGM sealed batteries, the acid is absorbed between the plates and immobilized by a very fine fiberglass mat. No silica gel is necessary. This glass mat absorbs and immobilizes the acid while still keeping the acid available to the plates. This allows a fast reaction between acid and plate material.
The AGM battery has an extremely low internal electrical resistance. This, combined with faster acid migration, allows the AGM batteries to deliver and absorb higher rates of amperage than other sealed batteries during discharging and charging. In addition, AGM technology batteries can be charged at normal lead-acid regulated charging voltages, therefore, it is not necessary to recalibrate charging systems or purchase special chargers.

Fairly pricey need to shop around but Varta do a good replacement, needs to have a higher charge rate a la CTEK conditioner.
Can develop/generate odd symptoms if running down.

[silverspeed]

Blimey your battery hasn't lasted very long? You sure it's the battery.

[mikey k]

Pilgrim - the Aston/Varta fitment I think is 595 402 080 which is not AGM
Silverspeed - no I'm not and it will be discussed with the dealer as a warratny issue tomorrow

AGM equivalents range from £105 to £425 (though the last lot are having a I think!)
They do hold charge better, are lighter, have higher cranking ampage and as we all know modern Astons like some amps even when stood still!

[Jockman]

mikey k said:

...as we all know modern Astons like some amps even when stood still!

Fat chance of your V8V ever standing still, judging by your recent excellent posting

[Murph7355]

I'm fairly sure it's an AGM. It looks very similar to the one on my 7 (a Varley Red Top), though slightly bigger dimensionally.

If you keep it hooked up to a maintainer it should last a long time (my 7's battery is a good 10yrs old at least). But they do not like being fully discharged.

They're a LOT lighter than traditional car batteries. IIRC this alone saved over 6kg of weight on the 7.

[mikey k]

Jockman said:

Fat chance of your V8V ever standing still, judging by your recent excellent posting

I suspect it was struggling during the trip and the prolonged runs kept it going. Or maybe the trip killed it? Anyway off to the Highlands in September so I need to get it sorted.

Murph - still not convinced it is AGM as the manual states its a 90ah Varta and those that size are std lead acid. Either way it has always been on the maintainer when stood for more than a week. I'll have a nose in there tomorrow evening.

[pilgrim7777]

Mikeyk- if you are not sure it is the battery then I would start to look at the alternator or the pulley and belt as on the the early models there was a batch of duff pulleys causing the drive belt to slip.
It does sound as it maybe spurious symptoms as the battery should last longer than 4 years providing it is kept charged.

[Jockman]

pilgrim7777 said:

look at the alternator or the pulley and belt...It does sound as it maybe spurious symptoms as the battery should last longer than 4 years providing it is kept charged.

Agreed.

Now you are definitely in the warranty area, and this could inadvertently be a godsend with your's lapsing in September

[JohnG1]

Slight hijack of thread but - the Varta battery weighs 22kgs.

Has anyone looked at using a Lithium Ion battery as a neat way to save weight - although expensive - probably about £1,800 - if you can save 15kgs then it's on a cost basis about the same as forged wheels, lightweight seats, lighweight exhaust.

Any thoughts?

[peterr96]

Jockman said:

Agreed.

Now you are definitely in the warranty area, and this could inadvertently be a godsend with your's lapsing in September

Also agreed. The road trip you just did would've been the nicest way to treat the battery. Lots of use over a number of days with long charging cycles doesn't sound like a battery killer to me. Standing idle in the garage for weeks/months, with no conditioner = good way to knacker a battery.

That said I'm amazed how well ours holds up with only predominantly weekend use. I do tend to use the conditioner over winter, but in summer (touch wood) never had any issue.

I'd get out there and buy a lottery ticket as it sounds as if you were lucky to get back without the car being on a flat-bed!

[mikey k]

Charged battery voltage is 12.5V, this drops to 9V in two days, running with the alternator charging the battery voltage is 13.7V.
So alternator is OK.
IMHO Can only be one of two things, battery is dead (not holding charge) or there is leakage to earth somewhere, though to flatten a 90ah battery in two days I'd of thought it would have been obvious where the fault was
Strange thing is none of the electronics are playing up which again suggests the battery.

John G - Li ion batteries are not robust enough, the AGM technology is better. It saves a lot of weight (less lead!) holds charge better and gives higher peak A for the same size.

[yeti]

Any links to a suitable AGM battery for a DB9?

[andyxxx]

My car was doing the same – I was told to purchase a trickle charger, which I did but it got worse so AM said it was the battery and replaced it which made no difference.

In the end it was indeed an earth fault which AM traced to the cig lighter.

Now it holds charge for weeks.

Good luck

[mikey k]

Yeti the DB9 fitment is the same as the Vantage.
This is apparently good VFM

http://www.odysseybatteriesonline.com/odyssey/prod...

Other makes can be found cheaper.

Car is booked in with dealer next week.
I'm still favouring an earthing issue.

[Murph7355]

mikey k said:

Yeti the DB9 fitment is the same as the Vantage.
This is apparently good VFM

http://www.odysseybatteriesonline.com/odyssey/prod...

Other makes can be found cheaper.

Car is booked in with dealer next week.
I'm still favouring an earthing issue.

Are you sure that's the one?

I was convinced the one on my car's a lot smaller than that. But haven't looked at it for ages.

[mikey k]

No not measured it yet
That was their recommendation when I gave them the AM/Varta part no for the OEM battery

[Murph7355]

mikey k said:

No not measured it yet
That was their recommendation when I gave them the AM/Varta part no for the OEM battery

Having seen off a few bottles of wine I thought I'd go and check.

I should check more often under the influence. I must have been on something stronger last time as I was sure I saw a small lightweight battery in there.

Instead, there's a monster of a lead acid jobbie, just as per the size you note! Some cheeky fqer has nicked my lightweight battery

[mikey k]

Murph7355 said:

Instead, there's a monster of a lead acid jobbie, just as per the size you note! Some cheeky fqer has nicked my lightweight battery

the workshop manual actually states it needs two people to remove it!

[Murph7355]

I reckon you could get a much smaller/lighter battery in there with a modified bracket.