MidLifeCrisis wrote:What is the box which looks like it might say 'Relay' on it that seems to connect the split charge relay, the fridge, the 240V and 12v fuse box ...... ??
Agreed. This bit around the fridge relay is a little confusing.
If your fridge is a 3-way fridge, then the 240V supply can go direct to the fridge via an RCD, no relay required (You can always put a switch in-line if you don't want to use the RCD as a on/off switch).
The fridge relay is normally used for the 12V feed, to switch a direct 12V feed from the starter battery to the fridge, using the ignition as a trigger voltage. This stops the fridge draining the starter battery when the ignition is not switched on. Looking at the schematic there is a single output to the fridge (12v or 240v ?), but 3 inputs into the relay (Leisure Battery via the fuse box, Split charge, and 240v mains), I don't think this is correct. Generally a relay is used to switch a high current source on/off using a much lower current trigger. The relay trigger would need to be earthed on one side to allow the relay to close, thus passing the higher current (Assuming it's a normally open type relay)
I think most people avoid using the leisure battery for the fridge because of the high current it'll draw, flattening the battery very quickly.