'08 Vantage Battery Drain

[BewickPlace]

Firstly a thank you to all the contributors on the forum for the valuable information and insight they've shared with us all. I don't think i'd have managed to cope with the quirks of my Vantage without the information here.

I've had a consistent niggle with the battery usage on my car since I got bit 5 years ago 2nd owner. At the start I was unaware of the limited battery life and the risks of getting a flat battery when leaving the car over a 2 week summer holiday. Since then however I have bought my Ctek battery conditioner; replaced the battery itself 2 years ago (for an Enduroline 100mah 900 cca replacement, recommended in one of the threads).

The new battery has performed well, and with the occasional use of the conditioner I have managed to avoid a flat battery until the last few weeks when over a long golfing weekend (5 or 6 days) I returned to find my car dead.

My usage pattern is not good for the car with occasional short journeys and a 60 mile round trip only once or twice every two weeks. But only lasting a week was still a shock. I decided I needed to find a longer lasting solution than just buying a new battery every 2 years. The forums had plenty of commentary on the issues, but limited definitive figures allowing a true diagnosis of my situation.

I wanted to share the information I've gathered to provide more tangibility and seek your opinions on a solution.

Firstly Battery Drain (measured on the battery earth connection)
- drain reduced from 1.5-2,5a at the point the car was locked to a quiescent 100ma after approx. 4 minutes
- as systems were shutdown at around 1 min and 2 mins after locking (draw 0.6a & 0.3a respectively)
- timings varied slightly depending on if the boot was open or shut
- so the drain appears to be 100ma
- surprisingly the same end point was reached when using the battery disconnect switch.
- I do have a standard tracker fitted
- test was also done with door module fuses out, again 100ma stable drain after 4 minutes
- I wasn't sure which other fuses is is safe to try (Fuse 52 start button/tracker circuit)?
- conclusion I'm left with a constant drain of circa 100ma - that should give a battery life well above 5-6 days...

So onto the battery itself:
- The battery charges fine when the engine is running (14.5v)
- I can use the Ctek charger occasionally but it's less easy to leave connected whilst away
- Ctek performs fine, charges the battery and gives no errors
- I used the Recond. program when recovering from the flat battery after my holiday.
- Battery voltage does appear to drop quite quickly, and so I am now looking at that
- Voltage immediately after full charge - 13.0v
- Voltage after having let battery settle (30 mins) 12.5v
- Voltage after approx. 12 hours 12.2v
- looks to me that the battery is getting "old" and holding less of a charge, but should it get like this after only 2 years.
- It doesn't appear to be bad enough to fail, just not strong enough given the 100ma drain

I'd appreciate your comments on these figures and the initial conclusions I'm drawing. In particular I'd value suggestions as to what should be done to avoid this cycle of needing to replace the battery every 2 years. I think I read somewhere that AGM batteries are less prone to sulphation, should I replace with one of those?


Any help appreciated.

Edited by BewickPlace on Monday 24th October 12:27

[BewickPlace]

johnnyBv8 said:

Just updating on this - as per the OP, mine dropped to 0.1a after 20 mins, which is probably about right. I think my battery is giving up, despite being fairly new (and no doubt within warranty still!) so will be putting a new one in.

I suspect your tracker is still connected. Do you get the flashing light on the dash when you set off?

My AM garage have kindly offered to disconnect the tracker and re-programme the car accordingly - they've said it is an hours work, but have failed to quantify when the benefit will be - does anyone know? Unless the drain would come down to 10-20ma (like a normal car) then I can't see the value in paying for the tracker to be disconnected.

At around 10-20ma I think I would then be able to use a smallish solar panel to do the job of the battery conditioner and keep the battery topped up.

[BewickPlace]

Mansfield said:

I've used a battery disconnect switch for the last 5 years with no problems to start the car even after 6 weeks (winter) of no use.

Car is still on its orginal battery.

They are less than £10 and a few minutes to fit.

Edited by Mansfield on Thursday 27th October 04:54

I presume with this you are not using the in-line fuse (?), and thus totally disconnecting the battery so that it is subject to no drain. At the same time that would mean car unlocked and no alarm.

[BewickPlace]

johnnyBv8 said:

Yes, the red light does come on for the first 30-60 seconds of running. It's been "deactivated" by Eurowatch, which presumably just means no subscription! Apparently removing fuse 2 under the bonnet (tracker and clock) would give a test to see whether this reduces the drain.

Edited by johnnyBv8 on Thursday 27th October 13:50

Just done the fuse 2 test and the quiescent reading falls to 10ma which is a sensible level..

[BewickPlace]

A quick update for all.

Over the past few days I continued to test with fuse 2 out, where the load was circa 10ma, and the battery held it's voltage @ 12.5v.

My conclusion is that my drain has definitely been the tracker unit causing a drain in excess of 100ma and probably more at times. (although I don't have the data logger to check, but battery deterioration would suggest).

I have therefore been into my Aston specialist and they've disabled the tracker and re-flashed the car accordingly.

Now at home the quiescent load is circa 10ma and I'm hopeful I can now leave my car for reasonable periods without having the lottery of battery status on return. Figures crossed.

Thanks for all the help.