# Battery change



## shaz4473 (Sep 6, 2009)

My 2009 ttfsi has been sluggish in starting, no battery warning yet but battery was charged at a garage and within a couple of days when checked again garage said battery needs charged again. Low mileage car but I do lots of short journeys and know this decreases the life of a battey.

I have decided to get a new battery, can anyone help with a cople of questions?

How much should I expect to pay for a battery and also what sort of price would I expect to pay for fitting?

I have been looking at the knowledge section and see that it says to lower the windows slightly before key out of ignition and starting replacement procedure. Is this imperative as it won't be an audi garage and wonder if I should print off the procedure to give to the mechanic(don't want to appear cheeky but don't want other problems caused!)

Will I definitely need to reset the windows and remote key fobs?

Thanks for any help so I can be as knowledgeable as possible.


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## TT-driver (Sep 14, 2010)

I haven't changed a TT battery myself yet. But if mine would be equipped with battery terminals under the bonnet, I'd connect another battery to those terminals while changing the battery. That way I'd be sure to hold on to the data stored in the DIS, which otherwise is lost.

Another thing to observe is the gas outlet pipe of the battery. It must be used as the battery is inside the car and battery gases are toxic and corrosive.

The window down a bit is to be sure to be able to open and close the door without having any electric power in the car. As you may be aware, the window pops down about half an inch as you open the door. It needs electricity for doing so :wink:

No need to relearn the key fob as far as I'm aware. Initialising the window is window down. Push button down once more and keep it presses for a few seconds. Then window up release button, pull button up once more and keep it there for a few seconds. All this with the door closed as far as I'm aware. The auto fully down, auto fully closed should work again. It's described in the manual too.


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## Hoggy (May 8, 2002)

Hi, No info will be lost, perhaps the radio code, but I believe even that doesn't happen on Mk2. 
Here's a selection of batteries from ECP.. Bosch or Varta if you have a choice.

http://www.eurocarparts.com/car-battery

Window reset is easy if req, just ask.
Hoggy.


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## TT-driver (Sep 14, 2010)

The MK2 doesn't loose it's radio code. But when I connected my sub woofer I must have had my battery disconnected just a second or so. The DIS had lost details like total distance and mpg... Perhaps the MK2 is different from the MK1 in this respect.


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## Hoggy (May 8, 2002)

TT-driver said:


> The MK2 doesn't loose it's radio code. But when I connected my sub woofer I must have had my battery disconnected just a second or so. The DIS had lost details like total distance and mpg... Perhaps the MK2 is different from the MK1 in this respect.


Hi, My 2001 Mk1 doesn't even loose it's radio code after battery disconnect.
Hoggy.


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## shaz4473 (Sep 6, 2009)

Thanks for the helpful info.


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## technik21 (Mar 6, 2016)

Hi All

Just having a read through this and previous battery related posts for the MK2 8J

I'm waiting for a replacement Exide for my 2013 MK2 to arrive.

I've seen one or two posts mention that after replacing the OEM battery, that you need to use VCDS to enter the new battery details and spec.
Just wondering if this is actually the case?

The OEM battery is an Exide that has an additional bar code sticker, which presumably is from Audi for the battery setup.

The replacement Exide has a slightly higher CCA than the original.
Original is 80Ah 640A
New is 90Ah 720A
Exactly same dimensions too, and approved via Exide for this car.

I will as advised in this post, connect a 12V battery to the engine bay terminals while I change over batteries, but it was having to change the battery details via VCDS that I was uncertain about? I have a VCDS cable, so I can do this if necessary.

The other stuff (window reset, throttle body reset) seems straight forward, again if necessary.

Cheers all...


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## FNChaos (Nov 30, 2016)

technik21 said:


> I've seen one or two posts mention that after replacing the OEM battery, that you need to use VCDS to enter the new battery details and spec.
> Just wondering if this is actually the case?


Yes, you should re-code your new battery. If your battery has a sticker with a BEM code you should input that number. If not, you can fake the data.

If the new battery is a similar type / size as the one it is replacing (i.e. AGM to AGM, FC to FC) then the only thing you need to do is change the serial number.

Changing the serial number forces the charging algorithm to reset. (Your charging circuit modifies it's behavior over time to compensate for an aging / weak battery).

The serial number you use isn't critical as the system doesn't really care. If you don't know the number then you can always increment the existing number by 1.


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## SwissJetPilot (Apr 27, 2014)

This is what's in the KB -

viewtopic.php?f=43&t=369306


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## technik21 (Mar 6, 2016)

FNChaos said:


> The serial number you use isn't critical as the system doesn't really care. If you don't know the number then you can always increment the existing number by 1.


Thanks for clarifying this. 
My serial number ends with a letter, so presume I just need to change any one of the numbers shown within the whole serial No., and then in my case change the battery power value.

I investigated further about the BEM sticker (Battery Energy Management), and now it makes sense as to why this is done.
From what I understand, the car adapts to the demands on the electrical system (i.e allowing the lights on after unlocking the car), based on the battery condition in order to give the car more chance to have enough power to start the engine if the battery is in a deteriorating state or has been sat on the drive for weeks. I noticed this myself when I opened the tailgate, and noticed no interior boot light working.
Of course, I guess you know this, but thought it worth mentioning if anyone wasn't aware.

My battery is showing 11.9volts at rest. Still has enough juice to start the engine, but it's over 4 yrs old and thought best to change it before it eventually throws its hand in. My journeys are generally short.

Found an explanation here:
http://lang.bannerbatterien.com/banner/ ... ik_GB3.pdf

Thanks again :-D



SwissJetPilot said:


> This is what's in the KB -
> 
> viewtopic.php?f=43&t=369306


That's great, thanks for this


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## Jeeringtowser (Jan 6, 2018)

FNChaos said:


> technik21 said:
> 
> 
> > I've seen one or two posts mention that after replacing the OEM battery, that you need to use VCDS to enter the new battery details and spec.
> ...


Not wishing to show my ignorance!
How do you input this new information?
Regards
Chris


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## TT-driver (Sep 14, 2010)

As far as I'm aware the TT mk2 never was equipped with a battery management module. Therefore recoding shouldn't be necessary.

I replaced my original factory Varta battery 3,5 years ago for a 90Ah 720A Exide and all is good. No recoding, nothing. Mine is a 2006. I did keep my car under power while making the swap. Saved me from doing the windows thing + the engine CPU didn't loose any of its short time and long time adaptations.


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## technik21 (Mar 6, 2016)

[/quote]
Not wishing to show my ignorance!
How do you input this new information?
Regards
Chris[/quote]

Hi Chris

It's done via VCDS, and in my case on a 2013 model, there is battery management in place. I actually don't think it really matters if you just replace the battery without re-coding, as from what I understand, the system will work it out eventually.
I could be wrong there, but I just changed the battery serial number and altered the power amperage that was originally coded in the system, as advised previously.
I noticed after doing this, that the battery condition that was reported at 40%, was then reset to 100% .
Having a backup 12v supply during the swap out saves having to reset the other stuff as mentioned earlier.


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## Anakin (Apr 19, 2011)

my battery in my 2010 car seems to be struggling a little this winter. I would plug it into my ctek charger in the Garage but theres some BMW taking up all the room.


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## CurryMan (Nov 20, 2016)

My recent car battery experience ...

Just had this Yuasa fitted by halfords today which was in the sale: http://www.halfords.com/motoring/bulbs- ... ar-battery. Came with a 5 Year Warranty so quite pleased with that. 

My original Varta battery was beginning to struggle starting. I had my alternator and battery tested by Halfords and they confirmed my alternator was fine but my battery had lost capacity in half the cells. To be fair the battery was over 10 Years old so I can't really complain.

Not bothering with all this re-coding business, sure the car will work it out eventually.

Will let you know how this new one fairs. :mrgreen:


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## Essexaviator (Jan 10, 2012)

I agree with tt driver I changed mine and put another small battery on jump start terminals under bonnet and saved any loss of stats etc.
No probs.


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