[Robert2912]

Hi all,

I have a question to the group here. I want to replace the main battery and the aux battery of my 640i GC. Of course I know that I have to register the new main battery to make sure that it will be properly charged. I use ISTA D for that job.
Battery is a Varta Silver Dynamic AGM 105 Ah.

My question is about the small second battery (13Ah, also AGM), I remember that I have read somewhere that this auxiliary battery should be registered too.
Am I right or wrong?
And if I am right, how is this job done?

I couldn't find the option in ISTA.
Or I didn't search long enough 🤔

I hope someone here can shine a light on it!

Thanks,

Rob