Today I had to replace the wiring from the main battery to the DC-DC loader in the back. On our way to Burgruine Finkenstein I wanted to give the batteries a good charge, but back home I noticed that the loader did not work any more. I found out that the fuse I installed earlier under the hood of the car had blewn and the housing of the fuse was nearly melted. So today I changed the wiring from 4 mm² cables to 10 mm² and now installed the new fuse next to the drivers seat, so that I have easier access.
I already noticed that the old cable was getting warm when charging (3 meters each of 4mm² was a little weak) and wanted to replace it for some days now. After the rewiring (a nice 5 hour job with a lot of cursing – although the voyager is a big car, they managed to make everything for the hands of children) I noticed that the fuse housing still got warm, while the rest of the cable now stays cold. It seems like the 30 amp fuse is too weak, the charger seems to draw more power on the input to get 14 Volts with 20 AMP on the output. Tomorrow I will test it with a 40 AMP fuse. Hopefully it stays cold then, otherwise I have to replace the fuse housing as well. To me it seems like standard car-fuse housings have some limits regarding the power they can handle at the contacts.