Changing Battery

Morning All.

I have a Mk7 TSI, it has the original battery , which has now dropped to 12.2 V when left overnight or charged. Alternator is fine as well over 13v when engine running. The OE battery is a EFB 69Ah 360a, I need to replace it. I was going to fit a Bosch EFB 70Ah 650a. I have been told I will need to re code the ecu ? I do have a Carista if I have to, but seems strange. I could understand it if I was changing to a totally different type of battery . Any help gratefully received.

I’d double check your numbers. The alternator should put out 14V and 12V is what the battery should read after sitting over night.

As I said the alternator is giving well over 13v , actually 13.8 to be precise. A charged good condition battery should settle overnight should give approx 12.6v.