Leisure Battery Not Charging When Driving

Is your fridge working whilst you are driving?

Usually the fault behind this problem a break in the feed from the engine battery to the leisure battery charging and fridge.
When the engine starts the relay is pulled in connecting the leisure system to the engine battery. In normal operation, power is sent to both the fridge and leisure battery. Think of the relay as a Y connection with the bottom of the Y connected to the engine battery and the two tops connected to the fridge and the leisure battery.
If there is a break (a loose wire or blown fuse) in the bottom of the Y once the relay is activated current can flow directly from the leisure battery to the fridge (the fridge doesn't know its power is not coming from the engine battery) without any input from the engine battery, hence the fridge flattening the leisure battery.

There should be a connection from the engine battery going to the leisure side. Check for any blown fuses or broken connections in the vicinity of the engine battery.
Try and find the supply coming for the engine battery to the relay when you find the relay, it should be permanently live. The relay may not be a separate unit, in modern vans, they are often included as part of the PCB which manage all the stuff.
If it's an integrated CPB look for a heavy wire coming to a connection marked + BAT 1 or something similar, which would indicate it's the direct live supply from the engine side.
+BAT 2 or similar would be the live connection to the leisure battery

My split charge relay is inside the schaudt control box / charger,

latest is i've found a little blue box in the starter battery box, about 50mm x 50mm , 2 wires on one side - and + signs and one wire on the other side that says +.I have tested these three wires with the engine running and not running and they have no power whatsoever. the make on this box is Nordelettronica ,Itallian writing, ingresso alternatore sotto chiave on one side and uscita alternatore controllata on the other side. I have tried to upload a picture of it but i was unable to do so.

This Little blue box is what is known as a vsr (voltage sensor relay) and when the voltage from the battery reaches 13.7v it turns it on and then the leisure battery starts chargeing.Made a phone call to pat horan motorhomes and they could not have been more helpful. Thanks to them and thanks to all who helped here on this forum.

Did you get the charging solved?
Did you have to rel place the controller

Always nice to get feedback on the results. It all adds to the information available on the forum

Great stuff!