Moin together, now everyone will think, “one more battery question”. Let’s see: Built-in is an AGM battery VARTA or JCB 75Ah 420A 800A in an Audi A4 B9. The battery tester from Ancel tells this here (picture). I then tried to charge the battery with a CTEK MXS 7.0 over the contacts in the engine compartment (not directly over the poles, and battery is in the trunk anyway). Bulk phase went through within 10 minutes. Absorption phase takes 4-5 hours. mmt and next morning tested with multimeter: still 12.35V resting voltage – as before. I will start with the Battery Guard (see in the background from the picture). Lima delivers enough: 15V in idle – but a little bit ok. What to do, said Zeus? 1. Buying a new car battery: laugh, that’s not what it’s about 2. Reassemble car battery and charge it directly: yes, you can do it, only has the fun to work as described by Audi. In addition, there is a warranty on the car and I have there’s another “invoice” open. Does any of you have any idea what it might be about?