Audi A3 8Y 12V Battery replacement - EFB vs AGM
Hello all, I woke up on Friday to a dead car (2024 A3 8Y FL 35 TFSI MHEV), a dead 12V and a cascade of errors. No big issue, gave it a quick jump start, a long drive and now the battery is holding 11.7V at rest - basically meaning it's finished.
I straight away bought another battery, an AGM model from Varta, which should be a drop in replacement. Or is it? I spotted this strange excerpt in Erwin:
Section 1.2.2 is a section on EFB batteries. Section 1.2.1 is describing a wet battery and Section 1.2.3 is describing an AGM battery (with the same words "replace AGM with AGM".
Why would VAG require EFB for EFB replacement on the A3? My understanding was both EFB and AGM are suitable for stop start cars. The plan is to also update the battery adaptation to "AGM" using OBD11 when the battery is replaced to ensure the charging voltage and BMS works correctly. Is it a case of VAG just making sure that people don't swap in any random battery compared to stock and minimise risk of errors (i.e. people putting in a wet battery instrad of the OEM EFB)?