While preparing our Troll for the 'hopefully' coming years travel, I noticed that there is a small dip switch amongst the connectors on the Schaudt CSV 409A BIP panel. This is labeled GEL and Säure (acid). Our new battery has no marking on it so checked with the supplier today and found that it is a 'flooded' one. The BIP was set to GEL!

This means our new battery was receiving the wrong charge pattern for the last year.
The dip switch has now been changed to the acid setting and hopefully, the battery will survive.
Fingers crossed.

It is worth having a look for this dip switch if you have the later blue BIP installed in your van and checking it is set to match the leisure battery you have fitted.

Alan