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Help Please Battery coding

Gooders Nov 2, 2020

  1. Gooders

    Gooders Active Member VCDS Map User

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    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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  3. OliNix

    OliNix Registered User

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    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.
     
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  4. OliNix

    OliNix Registered User

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  5. audiwaterpump

    audiwaterpump Registered User

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    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?
     
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  6. OliNix

    OliNix Registered User

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    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
     
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  7. audiwaterpump

    audiwaterpump Registered User

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    I believe the UDS version allows one to enter in the details of Ah, battery manufacturer, etc.
     
  8. OliNix

    OliNix Registered User

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    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.
     
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  9. Gooders

    Gooders Active Member VCDS Map User

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    [​IMG]
    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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  10. OliNix

    OliNix Registered User

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    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
     
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  11. rum4mo

    rum4mo Registered User

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

    desertstorm Moderator Staff Member Moderator VCDS Map User

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    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.
     
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  14. desertstorm

    desertstorm Moderator Staff Member Moderator VCDS Map User

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    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.
     
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  15. OliNix

    OliNix Registered User

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    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
     
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  16. audiwaterpump

    audiwaterpump Registered User

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    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.
     
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  17. Gooders

    Gooders Active Member VCDS Map User

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    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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  18. rum4mo

    rum4mo Registered User

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    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!
     
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  19. audiwaterpump

    audiwaterpump Registered User

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    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.
     
  20. Gooders

    Gooders Active Member VCDS Map User

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