How I --would do it/did it.

Sounds like you’ve got the right idea. Take your time and don’t scrimp. Quality costs in my book but getting it right first time saves a lot of heartache (and cash) down the track. Regardless of management ability, you’ll have to do a bit of research and reading as it’s truly the only way. You’ll get a more than a few opinions, one of which will be mine) and you’ll have to decide what is best for you.

Under the bonnet, I’d suggest a Redarc BCDC1240. It’s a DCDC charger with an inbuilt MPPT solar controller (regulator) so you can plug your panels straight in. They are due for release in February. I have the current iteration in the ute managing the battery. I’d go a Hybrid Deep Cycle under th bonnet. One that allows for aux power and deep discharge capabilities while allowing enough cold cranking amps to start you up if and when needed. On the Redarc website you’ll find a series of wring diagrams for the ultimate dual battery set up which includes using your solenoid and including a switched jump start ability (no need for cables). Here is the link.

WIRING GUIDES

In the van – Yes AGM. They start at $300. I went for an America brand Powersonic due to quality and range of sizes available in various footprints. This allows a few more mounting options. They are around $500 for the 140 A/H. Size is really up to you dependant on need. Managing it all I’d recommend the Redarc BMS 1215. This is a one stop unit that has AC-DC charging, DCDC charging, Battery isolator, MPPT solar controller and a display unit that is exceptional in functionality and provides in one interface, every input/output reading and all the battery condition information that you require and would otherwise have use many separate displays for. The key is keeping it as simple as possible and that’s what the BMS will do. My wiring Diagrams became remarkably simple with these units.

DC Product Review

Solar, 80W will probably not be enough. Think somewhere in excess of 120W of panels again depending on need. With the two Redarc products, you won’t need any further controllers of displays for readout.

As for wiring, again you’ll need to figure what’s being drawn down the pipe and overcoming the loss through resistance. Do the sums and make your choice based on that.

It’s a start for you. You cannot escape some work on your behalf though. Good luck


Mick

P.S. It's sunny and I'm about to start sanding the house for a paint!

Hi Sailinghampster

It sure ain't raining in Perth but it is too hot to go outside (or at least it was yesterday). I am still trying to get my fire sprinkler system in place and we are in the middle of the fire season.

Mick obviously has some very good practical experience and on the same page as I would consider myself on - and the reference to cable size for current and distance in the Blog by John and Val is the same references I was using in the other thread which was apparently "technically incorrect" - but enough of that.

I would add the following comments (for what my opinion is worth).

1. consider using 2 Isolators as per the drawing on the Redarc web site Mick pointed you at - "1 or 2 SBI's with 2 auxilliary batteries" - in your case 3 Aux. batteries. If your intention is to have all 3 Aux. batteries connected back to your alternator for charging it will ease the initial statup charge current and possibly reduce the size of your cable from front of Ute to the batteries in the caravan. I guess it will also ease the current load on your alternator and it's associated components if this is a factor.

2. you will need to roughly work out the total current you expect to draw from your Ute Aux battery (within the ute) and also seperately work out the total current you expect to draw from your batteries in the Caravan in a worst case situation - eg. like the fridge going while you are running a pump and all the lights are on. List on a reply if you like all the appliances you expect to run off the 12 Volt system in each area (the Ute and the Van seperately) with makes and models and ideally the manufacturers spec for current draw and and minimum voltage requirements if you have them.

3. As I am nearing my own project start point for the electrics I am happy to work on this with you if you trust my opinion (and with the help and ideas of anyone else out there contributing) by way of drawings and cable estimates and suggestions - reply to my post as you like in this regard. There are so many variables (duty cylces of loads, how much batteries are discharged, etc) and so many specialist areas (solar, batteries and charging, cable sizing, regulations and standards, etc) that the input of people in these specific areas will be of significant help. And practical experience is always far better than theory and you can only take the theory so far before it becomes impractical. Information can be posted as replies for others to cross check and modify.

Ken

POINT 4/ Wouldn't use a cigarette plug, use a more robust one, hella or narva type of plug, much better. Merit type plugs

The following is my opinions :-))) I've had many setups over many years and these days I like to keep it simple and reliable for desert travel. So my opinions are:


1.Ute auxiliary Battery? (Yet to purchase) - I would install a 100Ah AGM in the canopy and leave just the single cranking battery under the bonnet. Reason: heat shortens battery life and an AGM is the best battery to run your Engel for 2-3 days. I use a Remco ($339). You also avoid the extra cost of a second battery tray. But you will need a good earth lead going back to the cranking battery.

2.Redarc 100amp Smart Battery Isolator SB112 already Purchased - OK not my first choice, but still a popular choice. I am a fan of Rotronics isolators such as their MH10 as they don't use solenoids to switch the current (costs twice as much as a Redarc though). I'm using my second Rotronics in 23 years and 5 vehicles. Solenoid isolators can fail in short time. I would not install a DC/DC charger because it will limit the charging current to 20A. My single AGM takes 40+Amps after a nights camping so it recharges the AGM quickly anyway.

3.Fuse box under dash to feed two way radio and extra cigarette points for navigator mp3 player etc in cab - Yes thats fine.

4.Feed to cigarette point in tray canopy for engel fridge and lights - I prefer to run the fridge off a much better connection - the 50A anderson plugs are cheap these days and you won't get a better connection for your fridge.

5.Power feed to Anderson plug at rear of tray to feed back to battery bank in Caravan - Yes thats the most common way. What are you planning for the earth? I'd suggest your earth from the anderson plug go to BOTH chassis and cranking battery (for reliability).

6.Tekonsha P3 brake controller already purchased yet to install - yep, just follow the instructions - I used 12G tinned wire to the power connections and 12G to the trailer plug.

7.Solar panel (80 watt?) on roof of tray canopy. On wish list. Will need a solar regulator close to the battery I know but size type wire size etc? - I don't use solar panels - my alternator supplies a heap more power and in my experience, 30-60 minutes driving per day will recharge the canopy AGM just as much and a good set of solar panels. But it all depends on how you like to camp - I go for a drive most days. If you mount it on your vehicle, you are committed to parking in the sun.

8.Two batterys in Caravan in parallel. (Yet to purchase – AGM?) - AGM are the best choice IMO, because they are the quickest to recharge. I have an on/off switch installed on my trailer battery so I can switch the batteries off in storage.

9.Central Fuse/ Master switching block Already purchased for boat a few years ago - Yes, you can install it, but I'd expect that you'll leave it turned on all the time no matter where you use it.

10.Two 12 volt water pumps. White water and grey water from shower to Macerater toilet - yep but water pumps don't consume much power.

11.Entire lighting system in 12 volts. No 240 volt lights - Go for LED lights because of low power consumption and they are less likely to attract insects. But I still use flush mount 13W fluoros under my canopy wings because they are such a great light.

12.Two (80 watt?)Solar panels and Regulator (Yet to purchase). Yep, if you plan on staying put for more than a few days and need to recharge the caravan batteries.

13.Projector Battery Charger 7 stage. Already owned. Clamped to both batteries???? - Yep sounds good.

14.240 volt wiring to power points only, a given and will be done professionally.

"So how about it? Can everyone tell me how they would do it regarding wire size and colour?" - I'll assume your Patrol alternator is about 100amp. I use the Rotronics fusible links for short-circuit protection on all auxillary batteries. Fuses can corrode with time and circuit breakers can shut off in hot weather and corrugated roads in my experience. I'd run tinned wire on all applications if you want the system to remain reliable in years to come. I'd run 6B&S wiring to the aux battery in the camper and then to the anderson plug and earth return. It covers almost all situations without the need for a calculator :-)) Colour - all pos is Red, all neg is black and the brake controller lead is best blue if you can get a blue wire in decent size (12G). Also run all red (pos) wire in split conduit for extra protection, and cable tie it to protect against vibration.

Cheers
phil

Hi People of power,

Firstly an apology for the apparent ignorance in not replying sooner.
Life is just not the same here in Rockhampton at the moment. Something to do with the excess of water.

The caravan is sitting pretty in what I suspect is probably about a meter plus of water. I had it up on blocks so couldn't move it even if I could have gotten to it. (Parked at another property)

Meanwhile there is a lot to digest and I thank the posters very much. When Life settles down and the project gets back on top of the list I will have to digest all and see what happens. I have decided to keep things separated with no connection (Power Feed wise) between the ute and the van.

Thanks again.

Cheers all.