All about one of the biggest mysteries about the build at the beginning - how was I going to give my Votronic VBCS Triple Charger a D+ connection when my van didn't have one? The only real solution I'd found involved splicing into a cable underneath the dashboard and I really didn't like this, so with the hint of finding a video talking about using a switch I went about trying to figure out to do this.

This is likely to apply to any Euro 5 engines onwards (possibly earlier too as I'm not that familiar with anything older) as well as a range of chargers as smart alternators mean that you can't rely on the voltage of the starter battery as indication that the engine is running, so battery to battery (B2B) chargers need something else to tell them that it's time to charge the leisure battery. While D+ simulators are sold by Votronic, they are not recommended for my particular charger because it also trickle chargers the starter battery and that increase in voltage may trick the simulator into thinking the engine is running, creating a pointless loop.

My solution was to simply wire a cable from the starter to the charger D+ input with a switch in it, giving me the control to define when the charger runs and when it doesn't. This does have the downside that you can forget to turn it off and flatten your battery, but it does have the advantage that you can leave it off in certain conditions like if your starter battery was recently run flat or the fuse has gone in the connection to the charger, the latter being the case for me on my first trip away.

Hope this video helps someone out there, it's probably the one that would have helped me the most if it had existed when I was doing this part of the build. But it was quite fun and satisfying figuring this out, even if the answer is super obvious to people who are more knowledgeable about 12V and auto electrics.