Thank you all for your replies. Where do find and how do I access the 12v breaker in the PSU?
The breaker would be one of the electrical circuit breakers on the front panel. You can access them directly without the Powerpart being opened.
If you refer to the manual (link I added earlier) you'll identify it as the 6Amp beaker, as all that breaker does is provide electricity to the internal 12v power unit (ie the thing that's suspected as not working). I've added a couple of shots of their manual and added a bit of poorly drawn labelling if that helps. Sorry about the handwriting with the mouse lol
It clearly shows that the 6A breaker only provides power to the 12v internal unit, which is why I've turned that off. In doing so it means my Powerpart's 12v internal unit is shut off so won't cause any issues later one, for example heaven forbid it go seriously wrong and burst into flames or anything!
That means the Victron power supply/charger I'm using is the sole source of power for the 12v camper systems via the leisure battery.
I hope that helps.
Bit more info here though:
Since delving into all this I've discovered that the Sterling B-B can allow up to 30 Amps from one battery to the other (ie leisure and vehicle batteries), whichever needs it at the time, which is its purpose I suppose. With this being the Transporter T6.1 it has the start-stop system and vehicle battery to match... and being of course diesel if has glow plugs to warm things before engine start... The result of all that? The engine might take a peak of 50 or more amps to heat the glow plugs and start the engine, which then needs to be put rapidly back into the start-stop vehicle battery... As a result the Sterling wakes up and drags as much as it can from the leisure battery side of things, especially if the voltage is nice after being topped up on the EHU... but also if on the EHU at the time it will shove as much amperage as it can to the vehicle battery until that's charged. The result of that is whatever 12v power unit is in the camper it tries to load that too, and given that the Powerpart internal 12v (actually rated at 13.8v I think) is effectively rated at 10A max output it's effectively like trying to short circuit the power unit's output! It simply can't deliver the demand.
Result of that is leisure battery gets a massive drain to top up vehicle battery and the 12v power supply is left floundering to keep that topped up.
I'm 99.99% convinced that's why the Powerpart internal power unit failed in the first place, it's simply not up to the demand. Given a couple of years use it's likely they're all packing up. If they were rated at 30A it might be ok, but they're not.
This is why I've opted not to swap out the Powerpart unit, whether the "new" versions are a direct swap or not. Using a higher quality, higher power rated power supply like the one I've now got I think is the best way, well for me it's working brilliantly anyway.
I hope this has been of help
