Dc-dc charger with PMS3 and combi master fridge relay

[Ct6]

First post here.

I’ve got a 2016 T6 conversion with a PMS3 control panel and a combi master relay which I think controls the fridge. Other than a currently not working solar panel with an opti-solar MPPT controller, I can’t immediately see any other leisure battery charging equipment. The van has a smart alternator.

I am now starting to think about a winter project to install a DC-DC charger and have read many of the threads here on the subject.

At this stage I would like if possible to just install the charger (probably Victron) and touch as little of the rest of the installation as possible. This being so:

1. What if anything do I need to do with the combi-master fridge relay?

2. Should I have another split charge relay somewhere?

2. What if anything do I need to do with the PMS3?

I have established from a supplier that I can leave the solar charging circuit as is (I will just replace the pv panel).

Any suggestions will be appreciated.

Thank you.

 

[Ct6]

Replying to this myself, I think what needs to happen is this:

1. Disconnect fridge relay as there will be no need for the fridge to be running from vehicle battery when on the move as the dc dc charger will ensure the leisure battery can do this. The PMS3 12v feed will power fridge when on EHU (need to test this though).

2. Assuming the combi master is also the main split charge relay also disconnect it from both vehicle and leisure battery. Depending on cable sizes/lengths possible reuse for the new DC-DC charger.

3. Keep PMS3 for EHU purposes and for convenience as hub for existing van wiring. But consider:

(a) bypassing/disconnecting the 12v charger side as this is not up to the job of keeping the LB fully charged, and providing instead for a separate 240v smart charger either wired into the switch if accessible or to be plugged into one of the 240v sockets as and when needed;

(b) keeping the 12v feed from the vehicle battery so that 12v from vehicle battery can be used as back up by switching the selector to “Car” when needed (need to trace feeds to see if this only works/suitable if still connected to a split charge relay); and

(c) while in there, add in a couple of additional USB sockets and a state of charge display.

I think that’s all but comments welcome.