battery discharge

carpetbagger

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Hi all
Have been reading a few write up about heated mirrors and leaving the switch in the centre position and draining the battery
I had a new battery fitted to my a6 c6 2.7 tdi avant about 3 months ago and all has been fine battery reading 100% on mmi as i was checking it every now and then
Started car tonight and it sounded slugish so checked mmi and it said 10% went for a long run and charged to 100% checked charging
14.1 with nothing on 13.8 loaded so i gues charging system o/k
Then noticed i had left heated mirrors on which i never had done before could this be the issue
turned it off so will see
 
When you say long drive how long is that, it takes hours for a battery to fully charge.
 
The car was standing for 2 days and i took it for a drive for an hour have read on other sites that it could be the mmi not shutting down
will go to car now and check battery on mmi
 
Car has been standing for nearly five hours just checked battery showing 100%
all points to heated mirrors ???
 
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Thers the original cradle and phone in the armrest which i do not use just use the bluetooth with my phone
see what you are saying with the charge time
will go to powerhouse and get a battery check done still under warranty (good job at the price the are )
Still bugging me that the only thing out of place was the heated mirrors setting
 
out of interest how do you leave heated mirrors on, just by leaving the knob in the middle??? I always thought it was more intelligent than that...
 
Totally agree with you it should shut down when you take key out
not saying it is due to the heated mirrors it,s the only thing that i can say i did different
could it be the moduel ( relay )not shutting down it should not make any difference if it is on heated mirrors or not
is there a way of testing might just leave it on and see if it does it again
 
Out of interest what MMI firmware are you running, the final version was 5570, could be worth upgrading if your out of date. However I would make sure that the battery has been fully charged up using a battery charger before upgrading, as the BT module can take a long time.
 
Hi thought about updating firmware but some say you need 3 discs some say one ,also a possibility of loosing some settings and corrupting ecu i am gettint tp tmc bluetooth 2012 map update
is it worth the risk if there is any
 
There is a risk, but over the years I've updated dozens of systems and only had one failed BT module, the disks you can buy from Audi at the cost of around £5 the part number for the 3 disk set is 4L0 998 961
 
Cheers for that will give it some thought and see what benifits inget from an update going to check battery charge been standing all night and day fingers crossed
 
100% on MMI battery display isn't a good gauge as to battery charge/condition as it's totally ballpark.

Mine read 100% and took 5 days on a CTEK charger for that to advise of full charge/peak condition.

I ensure that any periods of non-use greater than 72hrs I have the battery on charge (in-situ) every couple of months and expect my battery (which is the original 2007 one) to last for another 3yrs minimum.

Natch not everyone has a driveway or garage to allow charging whilst in the car.
 
Will have to agree that the mmi battery display is not a good indication of battery charge once again after 2 days of not using the car the mmi read 10% about 30 mile round trip read 100% did the usual charging checks all o/k
So i put it on charge in situ and after 26 hours battery still not charged will go back to europarts let them test it looks like a duff battery
thanks for all your comments will post results of battery test
 
Its not a cheap item its a cbt (charger booster and tester) has charged numerous large batteries before on my vw lt 35 not a small battery and fully charges my old battery of the a6
Would i need to recode the battery if it turns out to be faulty as i suspect which i did not do when i put the new battery on
could this have caused any issues ??
 
Of the top of my head I cannot remember, but I'm sure I needed vag-com last time I changed the battery on the A6.
 
Not an issue i do have access to a launch diagnostic kit if needed i assume this kit will do the trick
 
Test of battery chargers seen here:

Battery chargers tested | Product Reviews | Auto Express

It took a full 5 days to totally recondition my 07 battery, so lucky I had another car to use, but as we know it's best to slow/intelligently charge our cars as opposed to getting the most robust charger with the highest rate :)

VCDS measuring blocks will show the true battery status and anything over 75% is good, anything below and it will need to be reconditioned, a good intelligent charger will be able to tell you if you need to replace, namely if it's still going after 5 days and VCDS doesn't show an improvement then you'd be best to replace it.
 
Totally agree with you it should shut down when you take key out
not saying it is due to the heated mirrors it,s the only thing that i can say i did different
could it be the moduel ( relay )not shutting down it should not make any difference if it is on heated mirrors or not
is there a way of testing might just leave it on and see if it does it again
Leave the mirror switch on the "on" position and go out to the car before you go to bed (air temp will be cooler) and see if the mirror glass is warm. If it is then the module to switch the heating off when you take the key out must be at fault as the mirrors should not be active when the car is switched off and locked
 

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