My weekend task that took a while longer than I expected! Finally got the stereo working from either the starter or the house battery. As the house battery has plenty of solar and I had upgraded all the speakers it made sense and I wish I had done it earlier.
In my case, I don’t have a split charge relay in the engine bay any more, so I have no house power there to split off. My relay is in the back. So running in cable time!
I used a Carling double pole single throw (on-on) switch to switch both the main un-switched radio feed and the aux feed that powers it up. Now in one position it works in the normal way, switched on and off with the ignition and powered from the alternator, in the second its on and all power comes from the leisure battery. I would have used some slightly larger, better fit switches but they only came illuminated and were very expensive and the Carling had more options. I got an actuator with a battery engraved on it and a purple one which was on back order but seemed more fun (and arrived the next day)
I ran in a 4mm thinwall cable between the switch and behind the fridge following the existing speaker cables. To lift the carpet enough the seat has to come out. This then joined onto the old fridge cable that I upgraded in the past.
I have a 6-way fuse board in the back which replaces the original board. I hated that thing, it was heavy, I didn’t like the loom dragging out everytime I needed to get in there, all the screw holes were stripped (wood screws into plastic is not a sensible solution) and the bloody door was always hitting me on the head.
While I was doing a bit of rewiring for the new circuit, I also took the time to modify the rear vents with metal clips for the screws and added a new set in the middle of the largest vent. All mine were stripped and the vents banged about.