A4 B8 Battery Change

[jdragon]

After reading a number of threads with conflicting info, I wanted to share my experience.

My B8 was fitted with the original Moll 8k0 915 105 E 12V 450A 95Ah DIN (760A EN/SAE) battery, but it was no longer holding charge so I opted to replace it with a G3 Varta Blue Dynamic 12V 95Ah 800A at a cost of £98.94 (inc VAT and del.)

I didn't bother with connecting a backup power source, so there was about 10 minutes or so with no power in the system which didn't cause any issues later. Once the new battery was connected, I checked the power meter in the MMI but it was greyed out; curiosity go the better of me so I started the car and still greyed out.

Fortunately I had borrowed my mates VCDS setup and coded as follows:

[19 - CAN-Gateway]
[Long Adaptation-0A]
[Channel] 004
[Read]

For my car, I did the following: Part number remained the same* | Changed the manufacturer code to VA0 | Entered the date and last 4 digits of the number etched into the battery

8K0915105E VA0 YYMMDDSSSS

[Test]
[Save]
[Done, Go Back]
[Close Controller, Go Back - 06]

Started the car and the MMI battery state was at 100%

I checked measuring blocks 018, 019 & 020 showed the battery SOC was 86% and the MMI was displaying 100% (original battery was something like SOC 25%, MMI 40%)

Lots of people have success with just changing the last digit of the serial number. I also tried this method and the battery registered as 100% in the MMI but I thought it was a bit cleaner to add the date and battery specific data, albeit 4 digits following a similar format of the original BEM.

*It's probably worth mentioning there were 2 spaces between the part number and manufacturer code which I inadvertently removed and the code failed to accept until they were entered again.