AGM BATTERY ON OLDER VANTAGE

[Philipcollins340]

Hi All,
Contemplating getting an AGM battery for my 2007 Vantage. Normal batteries (Bosch) only last about 4 to to 5years.
I got 12 years out of an AGM battery on my BMW.
My question is:-
Has anyone successfully installed an AGM battery on an older Vantage bearing in mind that the AGM batteries require different charging characteristics.
Any help appreciated
Phil Collins

[AMV8Stuart]

Philipcollins340 said:

Hi All,
Contemplating getting an AGM battery for my 2007 Vantage. Normal batteries (Bosch) only last about 4 to to 5years.
I got 12 years out of an AGM battery on my BMW.
My question is:-
Has anyone successfully installed an AGM battery on an older Vantage bearing in mind that the AGM batteries require different charging characteristics.
Any help appreciated
Phil Collins

My 2006 came with an AGM when I got it in 2022 - I always kept it on a CTEK when in the garage so can't say if it lasted any longer but I would have thought that they should be lasting about 6/7 years from what others have said previously. I have thought about a lightweight (Deadweight Industries etc), both on the 2006 and now on the 2016, some say they charge fine due to having an in-built management system, others say otherwise, maybe one day.

[Philipcollins340]

Thanks Stuart,

Interesting as I saw a dramatic difference admittedly on a different car. My early experiences on the Vantage were disastrous as I had one of those E-Watch trackers fitted that drained the battery super quick. Now she is only consuming 10mA on standby so I am hoping for better things if an AGM battery is feasible
Main concern is that I hope the AGM battery does npt damage the car charging system.
Cheers
Phil

[5s Alive]

The AGM battery should not damage the car's charging system however the normal alternator charge rate for flooded lead acid is 14.1-14.3v which is below the 14.7-14.9v required by AGM batteries to reach a full charge and remain in tip-top condition.

This should not be a problem if you connect the car to a smart charger with an AGM cycle while it is garaged. Once up to 14.9v the charger will drop to a lower level of float/pulse maintenance charge.

Ctek type smart chargers should not damage the cars electronics either.

I say 'should' because I'm not familiar with Aston 12v systems so probably best to seek advice from those who have done this before - which is no doubt what you are doing here.

[AMV8Stuart]

Philipcollins340 said:

Thanks Stuart,

Interesting as I saw a dramatic difference admittedly on a different car. My early experiences on the Vantage were disastrous as I had one of those E-Watch trackers fitted that drained the battery super quick. Now she is only consuming 10mA on standby so I am hoping for better things if an AGM battery is feasible
Main concern is that I hope the AGM battery does npt damage the car charging system.
Cheers
Phil

There are 2 things which affect the parasitic drain the most in my experience:
The original tracker - most people have them disconnected and coded out. The later versions were Cobra/Vodafone which seem to have a totally different drain.
The alarm system/sounder - if the internal board and/or battery go bad it continually takes power from the main battery rather than its internal which charges as necessary. Once I changed my sounder and upgraded the battery I did notice a difference in drain rate.

[V12VQuantum]

I've got an AGM battery in my 2009 v12v, no issues. Fitted before my ownership, so has been in for a few years.
Standard car other than a third party Tracker.

Charges on a normal Ctek trickle charger as you'd expect.

[Philipcollins340]

Thanks for the information. I just read that the normal wet lead acid charging voltage undercharges an AGM battery that reduces its life. Now confused and dont know where to go from here.

I think I will look at the charging voltage of the Vantage alternator and compare with the recommended AGM charging voltage and make a decision based on that.

[LPH]

I fitted a Varta AGM 019 Car Battery to mine 2007 V8V about 18 months ago after the last battery died.

Straight swap, still use my Ctek no issues at all.

I say 'straight swap' - whoever decided to locate the battery where it is needs a good talking to!

[Philipcollins340]

Thanks for your input.
Anyone had an AGM battery last >6years in an old(pre AGM battery) Vantage?

[Dewi 2]

Philipcollins340 said:

Hi All,
Contemplating getting an AGM battery for my 2007 Vantage. Normal batteries (Bosch) only last about 4 to to 5years.
I got 12 years out of an AGM battery on my BMW.
My question is:-
Has anyone successfully installed an AGM battery on an older Vantage bearing in mind that the AGM batteries require different charging characteristics.
Any help appreciated
Phil Collins

You might be unlucky with batteries, Phil.
The OEM battery on my 2009 V8V was still going fine in year 8.
Thought I might be pushing my luck, so having read here that removal and installation can be finger scraping, I had it changed at
service in year 8.
That has been the only change of battery, so therefore the second one is now 7 years old.

Perhaps always using a conditioner helps.

[Philipcollins340]

Just measured the battery voltage - engine running on the Vantage with current (knackered) non AGM Battery fitted. Its 14.5v which is a little low for AGM I think

[Buster73]

LPH said:

I say 'straight swap' - whoever decided to locate the battery where it is needs a good talking to!

Couldn’t agree more .

Being 6’3” didn’t make it any easier mind.

[Davil]

Another option is a Lithium battery. I have one and find it to be very good. I no longer use a battery conditioner. It also saves around 20kg in weight. I usually drive once a week but have left it for 2 weeks with no issues.

[Philipcollins340]

Just read about a ' mod ' to fool the alternator to put out a higher voltage to charge an AGM battery. It involves putting a diode in the sense wire that goes to the battery. This appears to increase the alternator out by 0.6v
Comments anyone?

[Philipcollins340]

Dewi 2 said:

You might be unlucky with batteries, Phil.
The OEM battery on my 2009 V8V was still going fine in year 8.
Thought I might be pushing my luck, so having read here that removal and installation can be finger scraping, I had it changed at
service in year 8.
That has been the only change of battery, so therefore the second one is now 7 years old.

Perhaps always using a conditioner helps.

Thanks Dewi,
With 2 Bosch batteries(correct spec) , I had the first one fail after 18 months(replaced under warranty ) and the second died after 5 years. Its definitey a car problem. The rapid discharge caused by the Eurowatch tracker is well known and even mentioned in the Vantage hand book. It flattens the battery in 22 days! The battery was spending too much time in a partially discharged state which will cause early battery death. I learned my lesson too late but had the tracker de- commission (can only done by an AM dealer). Problem gone away now.

[geresey]

Dewi 2 said:

Philipcollins340 said:

Hi All,
Contemplating getting an AGM battery for my 2007 Vantage. Normal batteries (Bosch) only last about 4 to to 5years.
I got 12 years out of an AGM battery on my BMW.
My question is:-
Has anyone successfully installed an AGM battery on an older Vantage bearing in mind that the AGM batteries require different charging characteristics.
Any help appreciated
Phil Collins

You might be unlucky with batteries, Phil.
The OEM battery on my 2009 V8V was still going fine in year 8.
Thought I might be pushing my luck, so having read here that removal and installation can be finger scraping, I had it changed at
service in year 8.
That has been the only change of battery, so therefore the second one is now 7 years old.

Perhaps always using a conditioner helps.

I just had 3rd standard battery on 15 year old vantage, and I think the previous change was 7-8 years ago per the history file, so seems about average life. This was a preemptive strike, in advance of a France trip. I’d had had a couple of glitches with the roof open/close, so had it checked and the garage confirmed the battery was on the way out, so replaced at service rather than risk any problems whilst away. It’s also been kept on a CTEK when not in use for the last 4 years (at least)

[Dewi 2]

Philipcollins340 said:

I learned my lesson too late, but had the tracker de-commission (can only done by an AM dealer).

Not only AM dealers. At least one independent can do it.
Presume therefore that AMDS kit must be required.

[Philipcollins340]

Thinking that the shortening of the battery life is being caused by the car battery spending much of its life in a discharged state, I have done a discharge test on the Vantage with a meter in series with the battery to look at the profile after the car has been locked and left.

1. The initial power draw is 2.5A falling to 1.5A after about 5 minutes.
2. Subsequently falls to 0.6/0.7 A after another 4 to 5 minutes.
3. Then a sudden drop to 10mA which seems to be the long term standby power draw. This is a good figure for any car! ( I did not look at the figure over a long period of time) All this does not amount to a significant discharge.

Lets do a quick calculation for a 95AH battery that has lost 80% of its capacity (to simulate an older battery)
Time to discharge the battery to 50% (meaning that you could still easily start the car):-
95 x 80% / 0.01A = 7600hrs ÷2 = 3800 hrs = 158 days!

This figure seems very much longer than what we are experiencing and does not really explain why so many people are replacing batteries sooner than expected. I know that many of you get good battery life so it must be the way we treat our batteries. It also brings into question why we have to keep our cars on a CTEK!
I have just replaced the battery for the first time on my 12 year old BMW and it has never been on a CTEK. it is, however used every day.
Your comments welcome

[Philipcollins340]

ALTERNATOR MODIFICATION FOR AGM battery ON OLDER VANTAGE



The AGM battery needs 0.7v more voltage that the standard flooded lead acid battery.
There is a simple, non-invasive modification that can be applied to the alternator regulator circuitry.
This has been done many times for other vehicles where older vehicles can benefit from the longer life and better charge retention offered by AGM batteries.

This can be done to the older Vantages. See the photos attached.
The mode takes the stock charging voltage from 14.3/14.4 V to 14.8v.
I have removed F30 from the engine bay fusebox and replaced it with a modified fuse. F30 sits in the alternator sense connection to the battery. I got a spare fuse I carefully broke the fuse element (I suppose you could achieve this by putting the fuse across a battery to blow it). I push a small twist drill up the middle of the fuse to break the element. I then cut off the top plastic part of the fuse to expose the top of the fuse connector strips.
I soldered a 1N4004 diode (not the one shown in the photograph) to the top of the exposed fuse tabs.
I replaced the fuse in the fusebox and it worked . I now have 14.8v charging my new AGM battery
NOTE THAT THE POLARITY OF THE FUSE-DIODE MUST BE CORRECT WITH CATHODE (Stripe mark) towards the Alternator and ANODE towards the BATTERY. The+12v battery connection of the fuse slot can be found with a test meter but see photo if in doubt

Comments welcome!

[Philipcollins340]

Update to AGM CHARGING MOD

Testing again today showed 15.2v which is a little over the maximum 15v recommended. I will try a Schottky diode to see if it gives the 14.8v or so. I tried this before and the forward voltage drop is 0.4v compared with
0.7v of a normal silicon diode.