The cheap charge controller I had installed gave up the ghost - or more like stopped reading the pack voltage correctly - and the next option, installing a PowerLog 6S to monitor the pack, also ended up with some smoke escaping and thus rendering that device inoperational as well. They run on the magic smoke, as you know. I now have some more electronic junk to be taken to recyling.
Cheap and readily available options exhausted, I figured what the hell, perhaps a local electronics repair shop could fix the original charger. The one that actually charges to a correct voltage right away. And what do you know, a couple of days in the care of Porin Radiohuolto and I once again had a working charger. Had to depart 85 euros for the job, but it's well worth it. These chargers do run at least around 500 € from China.
It had blown a fuse and a couple of caps had swollen, so they had replaced those. I had already suspected that I might have in fact aided in it's downtime by having it connected to the pack permanently, even while driving. It may have gotten on those caps a little and caused the fuse to blow.
So installing the charger back into the vehicle now, I added an 80 amp 12 VDC contactor, which only closes and connects the charger to the pack when the car is plugged into the mains. In the same power inlet as the main charger I just have a 12 VDC PSU originally from a Linksys router, which activates the contactor. I had a timer circuit as well, but decided to leave that out, just to keep it simple. In addition to the charger and the PSU there is also a aux battery charger, which keeps the small 12 VDC lead acid battery of the vehicle topped up.