DC to DC Charge System Questions.

[Paul#25]

I know this topic has been discussed many times on lots of other forums but I haven't really found the information I'm looking for.
The Jurgens Xplorer caravan that I purchased recently has a 12v system with a single battery as well as 220v system installed but I don't think it's all the original components. There is a Brad Harrison plug with heavy cables at the tow-hitch for connecting to the tow vehicle that looks like it connects directly to the caravan's battery.
As my Disco tow vehicle doesn't have an auxiliary 12v power supply to the back of the vehicle I'd like to install a supply and upgrade the caravan to a newer and safer spec than what is currently installed at the same time. As with most of my projects this must be done on a budget that is very limited so I don't want to waste money but still want to fit the correct equipment. At the moment I don't have solar panels to connect to the system but would like to make provision for a solar input at a later stage without having to replace what I fit now.
I see that the DC-DC chargers most recommended are the C-TEC, HCDP, National Luna and WRND. If I could get feedback from guys using the different systems and the reasons for using that specific one, it could help me decide what to install. I'd like to install the new cabling and plugs for connecting the Disco to the caravan using the lightest appropriate gauge wire possible.
Being able to draw on the collective knowledge of this group has been helpful before and I hope it will be beneficial once again.
Thanks. Paul.

[Rabbiddog RIP 7/6/21]

In my battery box I use a C-TEC which allows for solar panel input.

The cables running to the battery box are fused in the front and back of my Disco, using the lowest amp fuse's recommended which I tested which was 30A.
This is via standard wiring in the D3 which is rated for 30A, with factory fitted 30A fuses.

I don't know why LR fitted 2 fuses on the trailer feed, but they did, so I thought it better to use it than run new wires.

[ZR6SGN]

I have the HCDP power panel in the trailer. It works well with all three inputs; 12v from the car’s alternator, solar and 220v. It is awesome to have all this in one. It charges two 105ah batteries happily.

I have a Ctek 250d in the car. It works very well to keep one 105ah charged from either the alternator or solar.

I recommend that you use 16mm cable from the car’s battery to the rear.


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[Paul#25]

Peter, I haven't found any evidence of a feed to the back of the Disco 2. I'm trying to find anything suggesting that there is a feed in the wiring diagrams I've found.
ZR6SGN, I think the HCDP fitted in the caravan might be the best option. The current cable on the caravan isn't lekker. The insulation is hard and brittle so it has to be replaced. 16mm cable through the car and van will be the way to go.

[AndreasR]

Paul. Consider a portable power pack as in National Luna or HCDP. Best of three worlds. Can use it in the car, caravan or home. Versatility will get you most bang for your buck.

[grips]

Paul. Consider a portable power pack as in National Luna or HCDP. Best of three worlds. Can use it in the car, caravan or home. Versatility will get you most bang for your buck.

This is the best advice.

[Rabbiddog RIP 7/6/21]

I haven't checked the RAVE manual's, but if if you need to run a cable, I would suggest using 2 fuse's like they have on the D3, and use the lowest amperage fuse's required.

As Andreas said, portable power is the best way to go in y opinion.

[Paul#25]

I have a stand-alone battery that I used on the river trip for running the fridge in the car overnight but need to supply power to the caravan battery and system for its fridge while towing.
Looking at the Disco 2 manuals again, there is no provision for a power supply to the back of the vehicle other than the accessory socket that only has a max power rating of 180 Watts.
The safest way is going to be to run new 16mm cable from the Disco battery to the back of the car. Peter, on the Disco 3 system where are the 2 fuse's placed in the positive feed line. I would presume one would be close to the battery and the other close to the Brad Harrison plug at the back of the vehicle. I was planning on installing one fuse close to the battery and one in the caravan close to the charger that will be installed.

[Rabbiddog RIP 7/6/21]

On the D3 the front fuse is under the dash in the main fuse box, after a relay that kicks in when the power is turned on as well. The one at the back is in the side panel, with fuses for the trailer supply (Lights, permanent power and AUX power).

For yours I would suggest in the engine compartment, as close to the battery as possible and insulated from water ingress.
I take power after the rear fuse for my battery pack as it will let me know if the issue is in the wiring or battery pack

[Paul#25]

I landed up getting a National Luna DC - DC charger with the necessary 16mm cable and Brad Harrison plugs. Decided to start with the installation of the charger in the caravan and replace the wiring as needed. Was shocked to find that there are no fuses anywhere in the DC system. Where something has been added to the original wiring the wires were just wound together. Needless to say I've landed up removing all the wiring that I'm not happy with, replacing it with the correct gauge wire and using different colours for different systems. All of the system now go through the fuse box I've added. Once it's all finally connected and correctly routed I'll add photos here.

[Crips]

need to supply power to the caravan battery and system for its fridge while towing.

I charge mine on home with the standard built in Hercules system. Then on Friday hook up the Caravan and the fridge runs from the battery, go camp in the bush and Sunday at about 13pm the fridge will stop working.
So no "real" need to charge while towing if you go without power for just weekends

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[Paul#25]

Thanks for the info Chris. I'm trying to get it set up for longer trips now while I'm sorting out the old wiring. It's a pain to do it now but at least I'll happy that I'm not going to have problems later.

[Crips]

Thanks for the info Chris. I'm trying to get it set up for longer trips now while I'm sorting out the old wiring. It's a pain to do it now but at least I'll happy that I'm not going to have problems later.

Definitely, I see a lot of guys do 2 deep cycle batteries in the explorer and solar panels, according to them they can then camp indefinitely as long as they have water, the 2 batteries should last at least 3 days and in that time you should hopefully have some sun to charge up again

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[mplester]

For a number of years I always ran 16mm² cables from the main battery to the van. Then I changed this. I had a 150w solar panel fitted to the roof. The controller bolted to the battery box, and the panel connects to the 50a BH connector at the A frame. this way the battery is charged all the time whilst traveling.

[BushWacker]

Paul ,
I find HCDP units work very well...
I have one in/on a portable battery
box that I variously use
in the car(if I put the/a fridge there)
in the house
or in the campsite
or even in the trailer
(if that battery were to go flat)
I keep a 22OV to 12V charger to charge it or any other battery from the mains.
I have a 16mm cable connected to my cars charging battery with a fuse at the head ...
that cable ends in a an Anderson plug
that plugs into my battery box when its
behind my drivers seat otherwise it plugs into a further extension to the rear of my vehicle and then on to my trailer circuit ...
which has its own HCDP unit.
So I can, at will charge either my trailer battery or my battery box by
mains or alternator or a 100W solar panel
as I so arrange as appropriate.
I built the battery box myself with parts bought from BushPower ... but in retrospect
its better to pay a bit extra
and let the pro’s provide a neat working
co-ordinated system.
.