RG Colorado - Ctek 250s Dual Charger

Crocles
There is absolutely NO reason to fit any form of switch between the Ctec D 250s and your vehicle battery, as they are a one way only current flow and they also sense the alternator charge before they start to provide battery charge function, they also cease to provide any current flow to the van a short time after shutting the engine down so they will not discharge your starting battery. They are very similar to having a voltage sensitive relay but without the mechanical/electric system in the way they protect your starting battery.

I have used them in several caravans behind a LC 200TTD without any adverse effects over the past 4 years and over 70,000km of towing, only better charged van batteries.

Just run a good (6mm or better) supply from your starting battery, suitably protected by a 40amp fuse, to an Anderson Plug system, then similar cables to your Ctec D250s (located close to the battery) and then to the van battery.

Enjoy your travels
Athol

Some of the other 12 volt to 12 volt chargers need a trigger wire but not the Ctek.
There is only a wire from the alternator andsolar panel and the negative wires goes to the - pole. the only other wire is the heat sensor.

Honky

With advise like above no wonder why people get confused. The ctec web site has the ignition switching relay diagram for you to follow. It only needs to be a low current control wire like windscreen wiper circuit which is easy to get to.
I'd hope you've worked out that the solar panels get connected directly to the ctec and not the relay by now?
lc200 has a smart alternator and also benefits from ignition switching. They will work without it, just not very efficiently.

Have you got it sorted crocles?

And where did you finally pick up an ignition on source?

I have an LC 200 and a ctek 250 s fitted to my caravan. The simple answer is the wire for your ignition is the charge wire from your car which you would normally have coming through an Anderson plug. I also have the relay installed as per the standard ctek site drawing. The relay is used to select either power from the charge source automatically being the car or the solar panels. The car being the first choice. The selected input feeds into the solar input on the ctek rather than the car input terminal. My understanding is that the ctek has inbuilt protection to prevent the flattening of the car battery. In modern cars the voltage does not increase enough under load such as when you are trying to run your fridge and ctek to charge your van battery. Due to the to your ctek from the length of cable, load from your fridge, wire size etc... the ctek thinks your charge battery ( car ) is flat and will not charge your caravan battery to protect your car battery. By connecting to the solar input using a relay this input does not have the same low voltage battery protection and will charge your van battery.