Ctek in vehicle to Jayco power supply

Roger. Does the van have a Jayo fitted charger unit or is it a normal dcdc unit,? If inside a Jayco unit, most likely it will be operational from an ANDERSON supply via a direct cable. How old the van is will determine what to do, but NO you wouldn't dc to dc. Using good chassis Connections AND One heavy wire/cable to anderson won't cost $450 even with relay switching it as required.

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Hi Roger, certainly you can connect to the Jayco by running a cable from the Ctek to the rear of the vehicle but DO NOT connect it to the output of the Ctek. To do that would place more load on the Ctek and it is of no advantage. You can connect to the cable that presently feeds the Ctek, i.e. the input of the Ctek, but only if the size of that cable is adequate to feed both batteries. A much better way is to run a new cable from the engine battery (alternator) to an Anderson plug at the tow bar. This would not require an isolating relay as the dc-dc charger in the van acts as an isolator. Cutting corners usually results in unsatisfactory results.

Howl me down if the naysayers must, but the way I have my setup is working just fine for me.

In the back of my Landcruiser, I have a 100ah lithium battery that predominantly runs the fridge and lighting only. I have a 20A DC-DC connected to that from the vehicle batteries. This gives me a full charge to the 100ah in the back and has been working flawlessly for the last 3 years.

From there (that being the terminals of the battery, NOT from the DC-DC terminals as what you seem to indicate in your OP) I have run cables to an Anderson plug at the rear of the vehicle. That feeds/connects to the caravan where I have a single 120ah Lithium, charged by a 40A DC-DC. Again, this setup has worked perfectly for me for the last 3 years. I regularly check the battery monitors in the car and caravan to see voltage/amps in/out as well as battery % for the lithiums, so I can tell if the setup is working efficiently.

I also run a separate AndersonPlug/cable from the vehicle batteries to the caravan solely to power the 3 way fridge on 12V whilst travelling. If you are interested Roger, the cost of that for cables, "generic" Anderson plugs (about $2 each compared to about$10 for genuine) fuses and lugs etc would have cost me around $100 or thereabouts - with me doing the work. I don't have a relay on this circuit, rather I have a "Fridge Switch" at the back of the caravan fridge to cut the power when stopped - about $50.

The main requirement when I set this up was to run big enough cable which in my case was 6B&S. With the car running, I get a full 20A to the battery in the rear of the vehicle and close to the 40A in the caravan, dependent on the state of charges at the time.

I'll make a disclaimer - I am no auto electrician, but I think I have a reasonable idea of how to do things, and for many years, my setup has worked perfectly for me. I make sure I run cables that will easily do the job and I fuse the daylights out of everything !!

Hope this helps?

Dave

Roger,

I run 2 Ctek DC chargers.
One is connected to my secondary battery in the rear of my vehicle and the second is installed in the van.

I simply use an 8 B&S size Y patch lead to split the circuits.

The cable from the alternator is terminated with an Anderson connector. The Y patch lead is connected to this and the other two legs split into two separate circuits.
One provides connection to the vehicle's on-board Ctek DC charger and the other leg supplies the circuit to the caravan which feeds the Van's on-board Ctek DC charger.

As each circuit has a maximum current draw of 20 amps (determined by each charger) the feed from the alternator (also 8 B&S cable) can support both circuits.

As far as solar input is concerned, I have a 200 watt fixed panel on the van to keep its battery charged when off-grid and a second 200 watt portable panel to maintain charge on the vehicle's secondary battery.

Works extremely well for me and if I need to, the portable solar panel can also be connected to the solar input of the van's charger to further boost the charge going into the van battery.

Cheers,
Bill

Guy's thanks very much for your responses
Decided to go as follows if it meets your approval, working on the kiss principle
By doing this i hope to solve a few other problems such as space around the starter battery etc
6 B&S cabling, 50 amp circuit breaker at the battery and a straight run to the rear anderson plug
Have read that if you have a dc/dc (projecta PM335J) in the caravan you do not require any form of fusing or relay from the battery/alternator, not sure if this is correct
Noticed i have a 120 amp circuit breaker to the Ctek? when it only requires a 30 amp fuse!
Hope this was not the reason my Kings fridge packed it in
Another query, and checked my wiring diagram for Ctek, it only requires a 8 B&S cable, so if i had run a 6 B&S cable from the Ctek would this have not created a bottle neck?
Learning on the job :)