Page 2 of 2 FirstFirst 12
Results 11 to 19 of 19

Thread: Battery Replacement

  1. #11
    Verified VCDS User Zenerdiode's Avatar
    Join Date
    Jun 2014
    Location
    Newcastle, England
    Posts
    772
    Post Thanks / Like
    Quote Originally Posted by Uwe View Post
    I don't think there's any functional/physical difference between a BEM battery and non-BEM battery.
    I've had three batteries on my A4. The original, then two warranty replacements. Each time, the dealership workshop removed the sticker from the battery that had the BEM code on it. On my latest battery, you can even see a little 'click' in the under-label where the guy's fingernail picked at the sticker. I wonder why they did that? To stick to their paperwork to prove the battery has been changed?

    Not that they used the info... Before the recent introduction of the Battery History function to VCDS, I was tracking the battery serial number in the Adaptation Channels; and it never changed when they swapped the batteries. My only conclusion is when they changed it they just sent the existing details back to the module. Is there a function in ODIS to do that?

    They also didn't use a battery maintainer or workshop charger, because my History Data shows two change events of 26/10/2007 which is the date the clock defaults to when the battery is removed.

  2. Likes Uwe liked this post
  3. #12
    Verified VCDS User
    Join Date
    May 2014
    Location
    Melbourne, Australia
    Posts
    2,253
    Post Thanks / Like
    ^^^^^^^^^^^^^^ Arrhh............... now that's an interesting observation indeed!!! And it's entirely consistent with the settings in my data-base for every vehicle for the IDE03256-MAS06108-Battery adaptation-Battery Serial Number adaptation channel. Without exception, the value from the factory for this channel is 1111111111!

    Conclusion- the serial number (of itself) is not important for how the CAN Gateway manages battery operation !

    Don
    VW Golf MkVII (103TSI) my13

  4. #13
    Benevolent Dictator Uwe's Avatar
    Join Date
    Jan 2014
    Location
    Earth
    Posts
    17,198
    Post Thanks / Like
    Blog Entries
    1
    Quote Originally Posted by Zenerdiode View Post
    I've had three batteries on my A4. The original, then two warranty replacements. Each time, the dealership workshop removed the sticker from the battery that had the BEM code on it. On my latest battery, you can even see a little 'click' in the under-label where the guy's fingernail picked at the sticker. I wonder why they did that? To stick to their paperwork to prove the battery has been changed?
    I would suppose so, but I'm not sure.

    Quote Originally Posted by Zenerdiode View Post
    Not that they used the info... Before the recent introduction of the Battery History function to VCDS, I was tracking the battery serial number in the Adaptation Channels; and it never changed when they swapped the batteries. My only conclusion is when they changed it they just sent the existing details back to the module.
    That's pretty much inexcusable.

    -Uwe-
    The engineering problems are likely insurmountable. It would be like proposing to land a rocket booster section on a barge floating in the middle of the ocean.

  5. #14
    Verified VCDS User
    Join Date
    May 2015
    Location
    Scotland
    Posts
    55
    Post Thanks / Like
    Been here done this 2yrs ago, all info in my How to Guide on Mk7 forum. I did post this link earlier in this thread & you do insist on going around in circles.

    Battery BEM codes are REDUNDENT on a Mk7 Golf & others which use the same BCM adaptions channels, these provide a different way of telling the BCM what type of battery you have.

    From the Main screen:-
    Select Control Module [Select]
    [19-CAN Gateway]
    Advanced Functions screen:-
    [Adaptions-10]
    New value choice screen:-
    Change the following four channels, inputting the relevant data about the new battery.
    IDE03256-MAS06105-Battery adaptation-Rated battery capacity,
    IDE03256-MAS06106-Battery adaptation-Battery technology,
    IDE03256-MAS06107-Battery adaptation-Battery manufacturer,
    IDE03256-MAS06108-Battery adaptation-Battery Serial Number,

    QUOTE from my guide;-"Battery BEM codes are now redundant with the above separate channels. The most important channels are, Rated battery capacity, Battery technology, & Battery Serial Number. For the Battery Serial Number, just change one digit of the old one. This channel tells the BCM that a new battery has been installed & to relearn the new battery & forget any “learnt values” for the old battery!"

  6. #15
    Benevolent Dictator Uwe's Avatar
    Join Date
    Jan 2014
    Location
    Earth
    Posts
    17,198
    Post Thanks / Like
    Blog Entries
    1
    Quote Originally Posted by VAG-Dave View Post
    QUOTE from my guide;-"Battery BEM codes are now redundant with the above separate channels. The most important channels are, Rated battery capacity, Battery technology, & Battery Serial Number. For the Battery Serial Number, just change one digit of the old one. This channel tells the BCM that a new battery has been installed & to relearn the new battery & forget any “learnt values” for the old battery!"
    That's true -- on cars that use this newer scheme. But some of the cars being discussed in this thread don't.

    -Uwe-
    The engineering problems are likely insurmountable. It would be like proposing to land a rocket booster section on a barge floating in the middle of the ocean.

  7. #16
    Verified VCDS User
    Join Date
    Sep 2017
    Location
    USA
    Posts
    3
    Post Thanks / Like

    A battery is a battery, apparently. ;)

    Tl;dr:
    • In a pinch, you can use any 12V battery that fits.
    • If you can only find/afford one from Wal-Mart or Tesco, that's ok. (literally, YMMV)
    • As long as the new battery is approximately the same capacity as the old one, you don't even need to re-code the control module, VAG admits.
    • If you do re-code, the serial number itself doesn't matter, it should just be different from the old one so the car knows something has changed.





    I had never given this all that much thought, but after doing some work on my 2010 Audi A5 (B8) I was digging a little bit further into the electrical system.

    Unlike lithium ion batteries for a cellphone or computer, there is zero logic in the actual batteries for these cars. Still, I thought there could be a chance that the control module in the vehicle[1] (or something upstream) might contain some sort of look-up table; given the lifetime of a vehicle, though, that seemed unlikely.

    -


    This short white-paper (in German, or in a passable translation into English by Google)[2] was published by the German company Moll; they provided the OEM battery when my vehicle was new and sell aftermarket "BEM-compatible" batteries. Moll straight-up says that a battery is a battery, and that they even confirmed directly with Audi in Ingolstadt that there's nothing wrong with not coding your vehicle for a new battery if doing so isn't practicable.


    -

    Like VAG-Dave mentioned, the new serial number only serves to inform the control module that there is a new battery[3]. Over time, the system will adapt itself to the new battery, just as it does to an aging battery or one transitioning from a hot to a cold country.

    If you can re-code, do it (make up a random serial number if needed); if not, there's no reason to stress. If you don't recode, though, you might try keeping the battery at least 50% charged for the first few hundred kilometers and the first week or two[4].

    - Jim

    --

    [1] Specifically a J367 Battery Monitor Control Unit, in my case, located at the end of the negative battery cable in the boot. It is connected via a single-wire LIN bus connection to J533

    Also, I found this:
    “Quick static current measurement” capability has been implemented on the battery data module. This function is started using the Scan Tool in the “extended adaptation” mode of the Data Bus On Board Diagnostic Interface J533. The measured static current is then indicated on the Scan Tool. This function allows a quick static current measurement to be performed without the need for labor-intensive preparation of the vehicle.
    So, besides monitoring battery temperature, current, and temperature, and controlling electrical loads based on capacity at the time (including locking out the starter if it thinks there's not enough energy), that's pretty much the whole enchilada. If you pull power usage logs from your control modules, having the correct serial number makes tracking things easier, too, but that's hardly a concern for most non-fleet users. It might be helpful if you're a dealer for battery warranty purposes or somesuch.

    [2] http://www.moll-batterien.de/dateien...e_Code_web.pdf
    http://translate.google.com/translat...e_Code_web.pdf

    [3] ... and perhaps communicates the rated capacity to pre-UDS modules, but that's not an issue if the replacement is the same size.

    [4] If you replace the battery in an emergency without coding it and don't make it to the workshop for a few weeks, you might actually want to think twice before re-coding it at that point... I imagine by then the system will have already re-adapted itself and by re-coding the module that progress would be reset. No harm, but probably not worth the time if you got to that point.
    Last edited by JimGrisham; 11-17-2017 at 04:04 PM. Reason: minor/formatting

  8. Likes jyoung8607, DV52 liked this post
  9. #17
    Benevolent Dictator Uwe's Avatar
    Join Date
    Jan 2014
    Location
    Earth
    Posts
    17,198
    Post Thanks / Like
    Blog Entries
    1
    Quote Originally Posted by JimGrisham View Post
    • In a pinch, you can use any 12V battery that fits.
    Agreed.

    Quote Originally Posted by JimGrisham View Post
    • If you can only find/afford one from Wal-Mart or Tesco, that's ok. (literally, YMMV)
    Agreed.

    Quote Originally Posted by JimGrisham View Post
    • As long as the new battery is approximately the same capacity as the old one, you don't even need to re-code the control module, VAG admits.
    This, I'm not so confident in. Some of these BEM systems are insufferably stupid. To demonstrate: Connect an adequate charger up to a C6/4F A6, but instead of connecting it the way it's supposed to be connected (negative lead to the chassis) connect both leads directly to the battery. Now the BEM will only see current coming out of the battery, not the current being put back in by the charger. In this state, it will command all manner of things to power down after a certain number of amp-hours have been "drained" from the battery, all while the system voltage is happily at 13.8V or higher -- a condition under which it it simply not plausible for the battery to actually be drained!

    Now you (and/or Audi) are asking me to believe that this thing will actually "learn" that a new battery has replaced an old one without any intervention? Color me skeptical.

    Quote Originally Posted by JimGrisham View Post
    • If you do re-code, the serial number itself doesn't matter, it should just be different from the old one so the car knows something has changed.
    Agreed. Doing nothing more than changing the serial number will cause the BEM to believe that a new battery, with the exact same characteristics as the old battery, has been installed.

    -Uwe-
    The engineering problems are likely insurmountable. It would be like proposing to land a rocket booster section on a barge floating in the middle of the ocean.

  10. Likes Da Tow'd, PetrolDave liked this post
  11. #18
    Verified VCDS User
    Join Date
    Sep 2017
    Location
    USA
    Posts
    3
    Post Thanks / Like
    Quote Originally Posted by Uwe View Post
    This, I'm not so confident in. Some of these BEM systems are insufferably stupid. To demonstrate: Connect an adequate charger up to a C6/4F A6, but instead of connecting it the way it's supposed to be connected (negative lead to the chassis) connect both leads directly to the battery. Now the BEM will only see current coming out of the battery, not the current being put back in by the charger. In this state, it will command all manner of things to power down after a certain number of amp-hours have been "drained" from the battery, all while the system voltage is happily at 13.8V or higher -- a condition under which it it simply not plausible for the battery to actually be drained!
    I'm not sure about the C6/4F, but on the B8 it won't see anything at all if you charge that way... the one and only current shunt is located in the BEM on the negative battery cable. It will notice a higher voltage, but won't know why (nor will it care, of course). Actually, that's pretty much exactly what you were saying... totally agree. It's a fairly dumb system[1].

    I be surprised, though, if anything over 13 volts wasn't interpreted as being connected to an alternator or workshop charger and thus bypassing shutdown routines... but that's probably going to be up to software logic in the specific power distribution control module, not a BEM. Also (disregarding surface charge effects), voltage is a fairly reliable state-of-charge indicator for lead-acid chemistry, unlike with NiMH or Li-Ion.



    Now you (and/or Audi) are asking me to believe that this thing will actually "learn" that a new battery has replaced an old one without any intervention? Color me skeptical.
    No, it won't learn that there's a new battery. It will, however, eventually (over several charge/discharge cycles?) recalibrate itself, in much the same way as a good GPS receiver slews to a corrected position instead of just jumping there in one step. I think of this in the same way as the throttle body is supposed to slowly re-adapt itself to your driving style after it is re-calibrated.[2][3]

    In fact, if I had to guess, entering a new serial number probably doesn't tell the module anything except to reset all adaptations to some default, erasing any assumptions on state of charge that may exist in the system.

    After, say, two weeks of driving, I would be surprised to find any significant difference between a vehicle re-coded following a battery change and an identical vehicle with just a dumb battery swap. That matches my experience, and tracks with the whitepaper from Moll.

    Cheers,

    - Jim


    --
    [1] (... and the B8 doesn't seem to shut down nearly as many systems as did my old D2... which is why I was manually performing an equalizing charge on my battery near the BEM in the first place)

    [2] That's good engineering, too: if a provided value is in-range and plausible, go with it, but then adjust based on reality as time goes on... this will eventually correct for minor calculation errors, manufacturing tolerances, mechanical and electronic wear, etc.

    [3] ... or telling your mechanic what you think the problem is with a vehicle. If it's plausible and you were right, it might save them some time; if you weren't, they'll figure it out eventually and charge you more.

  12. #19
    Benevolent Dictator Uwe's Avatar
    Join Date
    Jan 2014
    Location
    Earth
    Posts
    17,198
    Post Thanks / Like
    Blog Entries
    1
    Quote Originally Posted by JimGrisham View Post
    In fact, if I had to guess, entering a new serial number probably doesn't tell the module anything except to reset all adaptations to some default, erasing any assumptions on state of charge that may exist in the system.
    Are you aware that the BEM keeps track of total energy throughput, i.e. the total number of amp-hours that have been put into and taken back out of the battery? You should be able to find this in the measuring values. I would expect it bases certain assumptions regarding the battery's condition based on this value, otherwise why would it track it, and reset it to zero only when you code in a new battery?

    -Uwe-
    The engineering problems are likely insurmountable. It would be like proposing to land a rocket booster section on a barge floating in the middle of the ocean.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •