Audi A6 Battery / Charging System issues

[dishy]

Hi I am having issues with my 2010 Audi A6 petrol battery and starting system.


The car started ok a few weeks ago after 8 days in the garage whilst we were on holiday. I used it to travel 20-30 odd miles. It was then left in the garage again for another 4 days and now it won't start.


Tried charging the battery but I have noticed it charges but then discharges. I can get it jumped started and after having done so driven it at an average speed of 35mph for 40 mins. However upon switching off and back on again there is no charge in the battery.


The voltage on a discharged battery is 9.6volts and when the engine is running the voltage is 14.7v, indicating that the alternator is pushing current into the battery.


Has anyone experienced anything like this before? I suspect that the battery is damaged and is not holding any charge. My mechanic is on holiday and I am loathed to get anyone else in or take the car to Halfords/Kwik Fit.

[ragebe]

Have a search on here, plenty of threads and posts. I'm convinced the problems I experienced with my A6 battery (same as yours) Were initially caused by water being retained in various parts of the car, so you might want to check the plenum chambers and remove the stone-shield underneath (big plastic tray)

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[dishy]

The car was working fine until after the holiday and kept in a dry garage following a period of dry weather.

[ragebe]

Have you run a VCDS scan?

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[ragebe]

The other thing of course, is just the battery. Five years is the usual lifetime given (although it plenty last longer)

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[dishy]

I am hoping it is just a battery. I have had the low battery warning come on now and again. I haven't got a VCDS though my mechanic does I believe.

[ragebe]

Have you looked on the VCDS map to see if someone is close to you?

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[dishy]

Yes no one close by - 15 miles is the nearest so would only work if they were driving by.

[MarkTM]

If the battery has a 4F0 reference on top, since you've not said you've had the car from new, it's most certainly the issue.

It doesn't need a mechanic to change if you go like-for-like in all aspects, if a recent purchase then many motor traders stick any battery in for resale, and the one fitted may not be the right one.

Since you've not stated your engine size no one can guess as to which battery you have/need, but regardless a replacement will be circa £100 max inc delivery

PS: It helps to put your location in your profile, so that it shows, you may be my neighbor but I simply don't know!

[dishy]

The battery in question has reference 8K0 915 105 and is a Moll 12V, 380A, 80Ah, 640A. It is fitted to a 2.0 TFSI (125kw) petrol engine and I bought the car last year second hand. Can I install an AGM battery into the car even though it doesn't have stop/start?