Battery drain

[AlanMcM82]

Hi guys, approx 4 months ago car developed a battery drain and I asummed it was the battery and replaced it with a new one. Everything has been fine since then until the last few days, where it is doing the same thing again. I have been jumping the car twice a day, before and after work from the old battery I charged up at home and having to leave the boot open so I can get access to the current battery and the old one as its now in the boot as well. 

Is their an easy way to find the fault? or is their a way of accessing the boot without climbing through the back of the car to do so?

I did have a drum of water in the boot that spilled and filled the spare wheel well and has soaked the battery management module and im not sure if this could be causing the problem. Previously when the fault developed there was no ingress of water so im skeptical.

 

Alternatively is their anything under the bonnet that can be disconnected and reconnected each time to cut the power from the car while not is use?

 

Thanks Alan

[Magnet]

Hello Alan,

You seem to suggest that your battery is now discharging within the working day. Is that the case? If so, you have some major ‘parasitic’ drain. 

Water and electrics and battery control module? Obviously not a good recipe, but since you had issues prior, then there may well still be residual issues. 

Unless you have the meters and skills, I would invest in an hour’s labour with a trusted local auto electrician with some urgency. 

Kind regards,

Gareth. 

[AlanMcM82]

I've the clamp meter for the job, issue is car is drawing 0.1A after switch off and then 3 hours later when I checked it again it was still drawing the same amount. 

Went out last night after it sitting for 8 hours and the car started fine. Left it over night and then this morning the car started fine again. It's baffling as to what the problem is. Maybe the control module has dried out and corrected itself. Would any of the windows being down affect the battery drain? Or would not locking the car with the remote cause it? Both of these occasions I did not lock the car with the remote and car was fine. I have locked it via the remote this morning so will see how it performs tonight when I finish work. 

[Magnet]

Hello Alan,

Many thanks. Detail is indeed king and allows more meaningful advice to be given.

100mA, although higher than it should be, should not be sufficient to cause you significant issues if the car is in daily use. 

As a general rule of thumb, around 50mA is normal after a fully locked down and alarmed car has been standing for a couple of minutes. 

What we are not sure about here is whether your (temporary?) issue has been caused by water ingress, or if there is still an underlying parasitic drain. 

It seems like you are well equipped to progress this, and it would be great if you could let us know how you get on. 

Kind regards,

Gareth. 

[AlanMcM82]

Right so battery still draining over night, came out and checked after leaving it 2 nights and it was sitting at 5V which is not even enough to open the boot. 

So using my old battery I charged up l use that to start the car. When the car is running the voltage is 13.3V so thinking now the actual problem is the alternator or voltage regulator. 

Does anyone have a DIY of the alternator change on a 3 litre diesel? Seen a few videos of taking the front bumper, radiator, headlights etc off to get access and don't fancy going that deep into the car. 

[AlanMcM82]

Latest update on this, I've been leaving the car unlocked overnight for the last 3 nights and every time I come out to start the car it starts with no issue and sounds strong when starting.

My usual commute to work is about 20mins there and 20 mins back so not sure if that's enough to charge the battery properly. So I've a good few days off and have been travelling about the place on long 2-3 hr drives and this should charge the battery properly and may have helped.

So tonight plan is to lock the car up and see what happens tomorrow. If it still starts fine then possibly just needed a good charge, if issue persists then looking at alternator and voltage regulator. I think the added drain of the alarm and immobiliser is possibly causing too much of a drain and results in not enough voltage to start. 

[Steve Q]

Hope that works 👍 if not I'm wondering if it's the alarm system draining it, especially as you left it unlocked. 

[Magic man]

Following with interest as i'm having the same problem!

I had problems with both battery and alternater around two years ago on my 3.0L Quattro and had them replaced. Lovely little expense!

The drivers door actuator played up in the winter but was ok in the summer. It since started again and so did my battery drain. During lockdown the car isn't getting it's daily use of course so initially i put it down to that. I since heard that if the actautor wasn't working properly (although it locked it just didn't unlock) the CCM wouldn't know that the car is locked and the sytems would not shut down causing battery to drain. I had the pleasure of changing the actuator the weekend. The battery was flat by the time i had done it???????? Anyhow i charged it up but i'm still having the same problems.

I've also parking sensor problems but can't see it being that. I've also recently found the soind proofing near the fuse box in the boot to be soaking wet!

Time for a new motor but i'd love to get to the bottom of this for my own sanity!

 

[eamon Austin]

Hi Iv just bought a second hand Audi A6 the guy I bought it from had battery drain he brought it to someone who took out the media 30a fuse and it has solved the drain issue.However I’ve  since found out that the Media software needed updated I got the Disc of eBay £25 and it’s all now working as it should. Hope this helps.

[RoyC]

On 7/6/2022 at 5:06 PM, eamon Austin said:

Hope this helps.

Thanks for that Eamon 

[RoyC]

This video may help

 

[RoyC]

If, like me, you have a 110ah battery, it has to be a big drain to flatten it in ten hours.

[bbrande]

I have a 2009 Audi a6 it rand and drove fine, no issues no stailling no problems dealer maintained, untill 105k, has 120k roughly now.. just had all lower/upper gaskets replaced and timing chain tensioners worked on. And everything was fine until I broke my back window while installing dyno mat on my trunk lid to prevent the rattling, but the whole thing shattered.. I went to the auto glass place and it took me 10 days to be able to order/get a new one, so I dropped it off at a shop cause it just stalled out on me 2x first time it needed a jump, second time it would not start. The battery keeps dying (witch was brand new 6mo old).. there was no check engine electrical issues, or anything else that could have caused the car to die.. after holding onto my car for 38 days, The shop called and told me it’s an electric problem and they cannot fix it, take it else where. I have yet to get a second opinion.. but the car was driving fine then just started stalling after the window broke and ofc it rained so stuff got wet in my trunk, is there anything that anyone could think of /recommend that may be of any benefit to my beautiful car! I would appreciate it if someone could help me with getting my baby running again. 

[Chax22]

On 9/11/2020 at 7:11 AM, AlanMcM82 said:

Latest update on this, I've been leaving the car unlocked overnight for the last 3 nights and every time I come out to start the car it starts with no issue and sounds strong when starting.

My usual commute to work is about 20mins there and 20 mins back so not sure if that's enough to charge the battery properly. So I've a good few days off and have been travelling about the place on long 2-3 hr drives and this should charge the battery properly and may have helped.

So tonight plan is to lock the car up and see what happens tomorrow. If it still starts fine then possibly just needed a good charge, if issue persists then looking at alternator and voltage regulator. I think the added drain of the alarm and immobiliser is possibly causing too much of a drain and results in not enough voltage to start. 

Did you ever solve this issue ? I’m having the same problem.

[Magnet]

Hello,

Before the questioning and answering starts, can you please complete your profile properly. 
Thanks.