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.
