In the EuroVan Camper there is a solenoid in the engine bay that charges the “house” battery - it is just a big switch, and has no “smarts” - it just combines the starting and house battery together while driving. Mine has always “just worked”.

Since I don’t leave well enough alone, I thought I would change it for something with some “smarts”, and something that would charge the starting battery when the house battery is being charged. As a bonus, I get the ability to use the house battery to start the van if the starting battery dies.

So I replaced the silver can that looks like something from a Ford truck made in 1930 with a sealed black box from Victron - the specific model is: Cyrix-ct 12/24-120.

Here is the solenoid, mounted on the firewall: Solenoid

I just had to change some wires from the battery, as well as replace a broken circuit breaker (which broke when I tried to loosen the connecting bolt) - not a difficult install, if you have the crimping tools.

Here is the Cyrix-Ct installed: Cyrix-Ct

Here is the Winnebago wiring diagram: Winnebago Wiring

Here is the wiring of the Cyrix-Ct: Cyrix-Ct Wiring

Note: it seems that Winnebago uses a #10 wire to the solenoid, then the rest of the run is #8, and the circuit breakers are 40 amp - which is the correct amperage for #8 wire (breakers and fuses are designed to protect wires). I just removed that #10 wire (which is utterly bizarre that it is not #8) when I rewired it. Just another “WTF?” Winnebago moment.