From memory, think you need a permanent live (fused) feed to the relay. Most are now electronic and you need to set the voltage threshold with a DVM so that the relay drops out when engine off and master battery volts drop to a pre-determined level otherwise the fridge and/or whatever else you have connected will drain the battery on the Berlingo. Think there used to be wiring diagrams in Towsure catalogues. I didn't wire the one on the Berlingo myself but it looked pretty straightforward..
Berlingo Multispace 2.0HDI '54 reg Mediterranean Blue
The following 1 user says Thank You to andy-womble for this post:1 user says Thank You to andy-womble for this post
Shouldnt affect Canbus as it is wired direct from the battery through a relay also powered by battery that senses when the alternator is charging.
Make sure that the supply taken from the battery area to the 12s socket is man enough to take the current needed to charge the caravan battery.
There should be a similar set up (possibly using the same relay) to power the fridge connection.
People do have problems with this set up because they do not understand about resistance and length of cable. It is approx 4m from the battery to the 12s socket and you can get quite a large voltage drop over that length. Most problems are caused by cables not being up to the job. Make sure that everything is fused.
The following 1 user says Thank You to Romahomepete for this post:1 user says Thank You to Romahomepete for this post
Thank you both.
A job to tackle over the winter.
Let you know how I get on....