Help Please Battery coding

Gooders

Active Member
VCDS Map User
Hello

I’m looking to replace my battery on a a4 b8 avant 3.0 TDi, I have seen mixed reviews on coding, has any one replaced on and if so what did you do? Also who went with an amg type and who didn’t?

Thanks in advance


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OliNix

Registered User
You need an AGM not an AMG battery

For the coding you are supposed to put in the new serial number and type of the battery. If you are just fitting another AGM battery then you just need to change a single digit and it will recognise it as a new one.

If you are fitting anything other than an AGM battery then you definitely need to recode it to the new battery type. It changes the way it charges the battery and the voltage cut offs.

If you are fitting another AGM battery you might get away without coding it, but why risk it? The change of serial number resets the charging profiles to what they should be for a new battery as opposed to an old one which won’t charge to full voltage any more.

It’s super simple to do. You just need someone with either VAGCOM, VCDS, OBDeleven or carista.
 

audiwaterpump

Registered User
But if the new battery (of the same type) is slightly more powerful (say 100Ah instead of 95Ah, and 900CCA instead of 760), and you only change one digit.
Will the car ecu still charge the new battery to it's full capacity, or just to the capacity of the old battery?
 

OliNix

Registered User
Pretty sure it only asks for battery type and serial #

State of charge is based off of voltage, so the car will never actually know how “charged” the battery is just if it is full or empty


OliNix
B8.5 S4 Avant - Glacier White
 

OliNix

Registered User
A little knowledge is a dangerous thing!

There is no such thing as a UDS version.... Whilst yes a UDS (Unified Diagnostic Service) routine will let you write a battery capacity somewhere in the module, I am 99% sure the B8/8.5 platform has no use for it.

I think the Q5 uses the capacity. It uses it to estimate battery state of health (SoH) by using something called a coulomb counter (think of it like an odometer for current) and then multiplying this by the Ah of the battery.

Even if your car did use this, the worst case would be the SoH in the MMI would be slightly off. When you put in the new battery serial number into VCDS, it resets the counter anyway. The Ah is only used for the calculation of the MMI SoH display.
 

Gooders

Active Member
VCDS Map User
You need an AGM not an AMG battery

For the coding you are supposed to put in the new serial number and type of the battery. If you are just fitting another AGM battery then you just need to change a single digit and it will recognise it as a new one.

If you are fitting anything other than an AGM battery then you definitely need to recode it to the new battery type. It changes the way it charges the battery and the voltage cut offs.

If you are fitting another AGM battery you might get away without coding it, but why risk it? The change of serial number resets the charging profiles to what they should be for a new battery as opposed to an old one which won’t charge to full voltage any more.

It’s super simple to do. You just need someone with either VAGCOM, VCDS, OBDeleven or carista.

f4bd9063f62bcaf88946189eabb99767.jpg

This is what I currently have fitted can’t see any ref to agm on it. It’s a moll make.
Was told a varta i1 would do the trick, it’s not stop start. I have vag com so should be able to sort it. Audi want £196 plus vat just to fit lol.


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OliNix

Registered User
You don’t have to use AGM. Any battery chemistry with the correct capacity and discharge rate will do.

Just make sure your coding matches the battery you install.

To be honest £196 + VAT is pretty reasonable. Even an equivalent Halfords 5 Year guarantee battery is £186 unfitted.

ECP have a range of 110Ah batteries from £183 to £236 (after a 40% discount code)

Im unsure what the question is that you want answered any more???

OliNix
B8.5 S4 Avant - Glacier White
 

desertstorm

Moderator
Staff member
Moderator
VCDS Map User
Have a look at Tayna, They have a list of equivalent batteries from Audi part numbers.
https://www.tayna.co.uk/Audi-Car-Batteries at the bottom of the page. Your battery is the same as mine that I changed several years ago.
I went for a Varta I1 which is the same spec battery as the OE item.
https://www.tayna.co.uk/car-batteries/varta/i1/
I happen to have a VCDS lead so did code my new battery by changing a digit on the existing serial number. The battery manager can start load shedding to enable the car to run and disable certain functionality. By coding the battery you tell the car it has a new one and it will immediately allow full operation again. If you don't code it then it will take a period of time to register that the battery capacity and health is a lot better, but it will get there.
You can nearly buy 2 batteries for the price Audi charge you just to code and change it.
 

OliNix

Registered User
@OliNix I think that you have miss read that posting, the £196+VAT was just a service charge to swop batteries and complete recoding.

I think you misread the OP's post. The £196 + VAT is just to fit the battery. The cost of coding and labor to fit it.

Ouch! My bad! See my previous post then. Buy a battery, use the VCDS map and pick up a spanner.


OliNix
B8.5 S4 Avant - Glacier White
 

audiwaterpump

Registered User
A little knowledge is a dangerous thing!

There is no such thing as a UDS version.... Whilst yes a UDS (Unified Diagnostic Service) routine will let you write a battery capacity somewhere in the module, I am 99% sure the B8/8.5 platform has no use for it.

I think the Q5 uses the capacity. It uses it to estimate battery state of health (SoH) by using something called a coulomb counter (think of it like an odometer for current) and then multiplying this by the Ah of the battery.

Even if your car did use this, the worst case would be the SoH in the MMI would be slightly off. When you put in the new battery serial number into VCDS, it resets the counter anyway. The Ah is only used for the calculation of the MMI SoH display.[/QUOMine

It can be........:thumbs up:

Mine uses the non UDS protocol.
I can only enter the BEM code.

I don't know which cars use the UDS. Maybe the Audi A8 does.
 

Gooders

Active Member
VCDS Map User
Lads

Thanks for all the advice, I’m not great with electricity lol, desert storm I’ll be ordering one in the morning and will use your method to code.
Once again massive thanks guys


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rum4mo

Registered User
It can be........:thumbs up:

Mine uses the non UDS protocol.
I can only enter the BEM code.

I don't know which cars use the UDS. Maybe the Audi A8 does.

All VW Group new models launched after roughly end of 2014 have binned BEM as the industry found it to be to very restrictive as it required the inputting of VW Group part numbers, very naughty!
 

audiwaterpump

Registered User
All VW Group new models launched after roughly end of 2014 have binned BEM as the industry found it to be to very restrictive as it required the inputting of VW Group part numbers, very naughty!
Yes, it does seem like they have used the computer coding of parts as a way to deter owners from using non VW Group parts.
The law tried to ban restrictive practices, but they found a way around it.
Good for VW, but not good for us owners who don't like being ripped off with exorbitant prices. Owners don't mind paying reasonable prices.
 

Jackorr

New Member
Hello

I’m looking to replace my battery on a a4 b8 avant 3.0 TDi, I have seen mixed reviews on coding, has any one replaced on and if so what did you do? Also who went with an amg type and who didn’t?

Thanks in advance


Sent from my iPad using Tapatalk
Gooders - I’m in the Kent area I have absolutely no idea how to message you normally instead of writing on an irrelevant post. Could you please drop me a message if you can to do with vcds as I’m very interested in it! Thank again

jack
 

rum4mo

Registered User
I am currently, re-visiting this topic, reason being is that I bought a new Bosch AGM battery for my 2011 B8 S4 - I know that changing a single digit of the serial number wil work perfectly well, but, I helped out a friend back last January with his A6 TDI that came to him with a lead acid battery and his local garage fitted a Yuasa AGM of the same size without changing any coding, at that time I considered that Audi never intended that model to ever use an AGM so swopping a lead acid for an AGM would just be correcting the previous owner's/selling dealership's error, so what I did was "all good". Now with a bit of time, I'm wondering if I should change the coding from lead acid to AGM - I have idea if the origin coding is for a lead acid or AGM battery, but if I could get access to that car I could read the battery info stored in the car's BMS and work that out.

Now my logic is, with these B8 cars all have the older BEM system, which means that you can't perform re-coding using Carista, it is just not an available option within Carista for B8 cars - I've checked recently.
So, within the BEM system, the VW Group part number must contain the battery "size" and "chemistry" as only the "part number" and "vendor" and "serial number" are directly accessible within "Adaption" in CAN-Gateway.
That leaves me thinking that if you dig deeply elsewhere in the CAN-Gateway, you should be able to find what the current "value" for "size" and "chemistry" is - though I'd think that just changing to suit would not work as the settings would now clash with what the "part number" forced these "values" to be, I think that somewhere in the readable stats I discovered "size" and the statement against that was "OK" which sorts of backs up my logic.
That would leave find a suitable part number to use to force the BMS to change and agree with that any change from lead acid to AGM was correct, I'm also just guessing that the only way that newer part numbers would end up in the BMS area or sub-module of CAN Gateway is via regular updates at your local Audi dealership! For the rest of us we would need to search the internet for lists or pictures of newer BEM labels for the correct type of battery.

Any/all of that wrong so far, if so please chip in, all of this is for others as I can just change a single digit to the existing serial number, but to date some of what I've written I have not been able to confirm or even find on the internet, as usual it is easy to find out most of what this is about, but not it all, I'm just trying to help that a bit even although for some who are not involved, this is just flogging a very old horse.

Edit:- BTW from memory, there is no reference as to what the present "battery technology/chemistry" setting is when looking up battery details within "Measuring Blocks/Basic Settings", just battery type - OK, battery vendor - 2, battery size - 11.
 
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rum4mo

Registered User
@JohnS3 , thanks for that, I've never been on that website before, the list of part numbers could be handy, I was going to look up some current listed ones on a VW Group parts listing site, I probably still will and add them if any newer ones have appeared to that list.

As always, many people seem to think that all this has been written able in the past many times, but the info like "useful part numbers" listed against size and type is not quite so freely available, so you adding that in has pulled more info into this thread.
 

JohnS3

Registered User
@rum4mo i changed my battery a few months ago and did a lot of research into the coding. I did find quite a few sites listing battery manufacturers/part numbers/serial numbers. These were old threads when BEM codes were relatively new. Sadly I didn’t bookmark them and a search around last night discovered the site I posted above. I’ll dig around some more and will post back if I can find them.
 

rum4mo

Registered User
@JohnS3 , yes I've found many as well so I could probably bump into them again, something in the link you provided seemed to mean get closer to answering questions that I still had, with one exception for anyone just coming into this topic, and that is, when the part numbers are listed against battery size and type, there is a claim that the "bits" in orange are part numbers and the "bits" in blue are serial numbers, that might have been the original plan but everything that is listed are part numbers only.

It is easy to use a QR reader with any of these pictures of BEM codes to reveal the complete strings of letters, numbers and symbols and so work out which part is the serial number and DOM code etc, along with facts like Varta seem to use VAO and VA0 etc etc.
 

rum4mo

Registered User
@JohnS3 , your offer to try to find the posts that helped has prompted me to try harder!

So on checking on the list of "Similar Threads" I have got all the info that I could possibly need for now, thanks again.
 
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