A6 2011 - Flat Battery & Replacing

[DJS11]

Hi All,

I’ve had a search for the answers and as yet unable to find them so i hope it’s okay to ask them here.
The car in question is a A6 2.0TDI diesel 2011, after the car has been stationary for a couple of weeks and what with the cold weather the battery is low and now only give around 5v. Putting the battery on a CTEK optimiser for a few days it run though the first two modes that given an error at the third stage reporting the battery won’t take a charge.

I’ve settled on a replacement battery is required and checked and sourced the matching model (H15 Varta Start-Stop Plus AGM Car Battery 12V 105Ah), i understand that the battery needed to be coded to the car using the details from the new battery, if i swap the batteries over will the car run before it’s coded? is the coding to help with the battery conditioning / management?
With the existing battery being so low (no electrics on the car at all) is there a chance of other problems such as key coding?
Just trying to prepare myself for what may happen and needs doing after the battery is replaced.

Thanks in advance.

[morski]

Just replace the battery and then code it later. Car will work fine and no need to recode keys etc. Coding the battery to the car is to tell the car that 'hey im fine just give me all the normal juice that i need no supplements plese'

[DJS11]

Thanks, will do.

[A6S]

I'm interested in what the actual coding does?
Surely it's just a 12v battery like any other one. Just needs to hold enough charge to keep car running

[Silane]

The BEM code on the battery allows the car to track what battery is installed. Then it learns parameters of the battery such as age, how well it charges, how much power it supplies etc and compensates for those things. When you put in a new battery without adding the new BEM code the car still compensates as though an old battery is there. But even without entering the BEM it will learn the characteristics of the new battery over time anyway. Some things like start/stop might not work as well/at all until the new battery characteristics are learned though.


See: http://www.bannerbatterien.com.cn/ba...echnik_GB3.pdf

[DJS11]

I'm pleased to say it was a straightforward swap and no real issues, one thing i have noticed is the start/stop hasn’t kicked in yet. I’m assuming this is because the car isn’t aware of the batteries condition yet?
I've only done a 40 minute return journey on top of local trips, will keep an eye on it, my plan is to ask if anyone local with VCDS can code it for beer tokens.

[AT.]

i have noticed is the start/stop hasn’t kicked in yet.

IMHO the ambient temperature is too cold to allow the use of the start/stop system.

The engine and the other systems could cold down too fast, so it doesn't worth to shut down the engine for some seconds, as a colder start could cause a harm in the engine, and it does not worth to take the risk to spare a minimum amount on the fuel consumption.

[johnsimcox]

IMHO the ambient temperature is too cold to allow the use of the start/stop system.

The engine and the other systems could cold down too fast, so it doesn't worth to shut down the engine for some seconds, as a colder start could cause a harm in the engine, and it does not worth to take the risk to spare a minimum amount on the fuel consumption.

OP is in Surrey where it is 8c this morning so ambient temperature is not an issue. Appreciate that in Hungary the temperature is somewhat colder

[AT.]

This argument doesn't sounds like a contradiction for me, because if you can believe, that the -2,5°C can affect whether the start/stop system will work or not, then there is no argument to declare, that the 8°C is such warm weather, when the start/stop system must work.

Honestly, I don't remember when was the last time, when the start/stop system stopped my engine for the last time.

Anyway it was just an idea.

[AT.]

OP is in Surrey where it is 8c this morning so ambient temperature is not an issue. Appreciate that in Hungary the temperature is somewhat colder

I just remembered this issue, and something strange happened to me yesterday and today. As I mentioned earlier, I don't remember when my start/stop worked for the last time. However yesterday I was surprised, as the start/stop worked for me, so I checked the temperature, and it was 8.0°C by the DIS.

However, today I stopped in a traffic jam, and the start/stop doesn't worked, so I checked the ambient temperature, and it was 7.5°C b to the DIS...

Strange

Strange indeed, maybe there were other reasons (ie. the engine was not fully heated today)