Battery replacement

[Mr V10]

Has anyone had to replace a battery on one of these? Mine is definitely on the way out, just about started earlier, and only a few bars on the MMI when I check.

Does the battery need to be coded in? Or can I just swap a new one in?

[Golfather]

No coding required.
But get it checked out first as it may just need a full charge.

[classba]

The battery do run flat quickly if you are working on the car for any reason and it will go down to say 10% if the car has not been started/ driven for a week or so. Mine gets like that occasionally and a 20-30 mins drive will charge it up fully. You can buy a great battery charger like the Ctek MXS-10 which also can check and recondition the battery.

[Golfather]

CTEK chargers, although pricey, are awesome quality and the best out there. Well worth having one.

You may also want to check any fault codes incase there are any buttons stuck on the MMI as that wont allow the system to fully shutdown and hence drain the battery.
eg:
02244 - Button in Control Head is Stuck
003 - Mechanical Failure - Intermittent

[adsgreen]

+1 get a conditioner.
Once a battery has dropped low once it'll never be the same as it'll start forming crystals on the metal plates. You'll show good voltage but capacity would be much lower.
The cold weather doesn't help as this naturally slows down the chemical reaction that outputs the volts. Batteries don't "go flat" in winter they just slow down - the charge is still there (assuming they don't freeze) so if you warm a battery up it'll start working again. I had to do this with my old lotus more than once with it's tiny tiny battery. Neighbours were quite amused.
The conditioner does voodoo (something like making the voltage oscillate) that breaks down the deposits (if only it worked on carbon ).
Completely safe to leave on all the time when parked up.

[Mr V10]

Thanks guys, but I know the battery is knackered, it has struggled to start (cranked) for about 7 secs a few weeks ago and that was after a longish journey, too. The CTEK thing, I don't get it... Does the CTEK unit itself not require any charging? By conditioning the battery, will it effectively repair my current battery? CTEK thing could be handy for Le Mans if it constantly keeps the car charged... I know what I want for Xmas if it works as I currently understand it...?!

[adsgreen]

It works like any other charger - you plug it into the mains
You can get units that are just conditioners that plug into the cigarette lighter socket but I've no direct experience of these.

The principle is the same though by modulating/changing/voodoo they very very subtly alter the characteristics of the electrical system. Not much and certainly not by enough to affect operation of the car but enough to cause a reaction in the battery breaking down the build up on the metal plates inside causing the issue. Think of it like bending a credit card back n forth... eventually it'll break.

if you have good volts then its a capacity issue and worth trying a conditioner first.

Alternatively you could buy a booster pack but to be honest, might as well just get a new battery.

[Mr V10]

Yep, I'm going for a new battery. I just remembered I have the AA breakdown repair cover so when it does eventually go flat they will come out and replace it FOC, Audi warranty doesn't cover battery.

Will maybe grab a Ctek thing for Le Mans though.

Thanks for your help, good to know it doesn't need coding like it does on the A8 models from 03 onwards.

[adsgreen]

If you are going to get a ctek at some point anyway why not get it now and see what it does? I've seen it recover batteries I thought were junk back to almost new.

[Mr V10]

That was the initial plan, until I remembered about the AA cover, I don't want it recovered now as the AA won't replace the battery, they do a battery test and only replace if it is dying.

[adsgreen]

just seems a lot of hassle for getting anew battery that'll probably be a cheap non-oem knock off.
As I understand it, You need to call the aa, they come and test, point to a possible battery issue then you have to rebook a battery fitment...
They don't carry batteries in the trucks.

[chunky79]

That was the initial plan, until I remembered about the AA cover, I don't want it recovered now as the AA won't replace the battery, they do a battery test and only replace if it is dying.

What? If you get a conditioner and it sorts the battery then you won't have to call the AA. And if it does play up after then they will change it, cause it's dead.
Too much hastke waiting for it to break down, what if you are out and about?

[Mr V10]

It won't 'fix' the battery though.

AA did it on my other car. Came out, swapped the battery. Done in 20 mins and in one visit. Probably just going to be a Bosch unit or something, if they can't do it there and then I can take it anywhere and claim the dough back.

I've told my sister I want the ctek thing for Xmas now anyway, so that's sorted.

[adsgreen]

It most probably will fix it though.
I've had batteries returned to near perfect that previously could barely hold 11v after days of charging.
Don't underestimate just how much voodoo there is in a battery conditioner

[imacool]

Does it have to be CTEK MXS-10? From a brief look on their web pages the differences between MXS-7 and 10 are the temp sensor and maximum output current.
Is it worth to go for the top model if chances are that I will never be in the need of charging a 200mAh battery?
Anyway,thanks for the info on these chargers.