Caravan 3rd Battery - Charge Power + Isolation

[berniebgf Senior Member Find all posts View Profile Close berniebgf]

Hi All,

Am wiring up the Prado in preparation for a caravan, I already have the dual battery setup in the 4b with the redarc SBI12.

I have a couple of questions, here is the setup I am looking at....

Positive of second battery -> 30amp (or 50amp) breaker (manual reset) -> Isolator (either redarc SBI12 or sidewinder DBi 140) ------------> Anderson plug to rear of 4b for caravan.

So the questions are.

1. Is the second isolator warranted? (I believe it is)
- I want to protect the 2nd battery if I have the caravan connected but the car off...If the fridge is on DC it will pull a bit of Juice (up to 10amp normal, maybe more on start up?).
2. Is the Breaker warranted? (Answer is Yes for me)
- Protect cable power capacity and battery in-case of cable issue / shot or some human turd shorts it.


Other comments
1. Caravan mob says they have a diode on the circuit to stop power flowing from the caravan to the car... Good. I must ask if they have any voltage drop isolator built in?.. Do new caravans usually come with that type of setup?

Using 6 B&S + Cabling with 50amp Anderson Plug.

Have looked at allot of different web sites for info, thought I would throw it out to the forum.

Thanks

Bernie.

[cmilton54 Find all posts View Profile Close cmilton54]

Hi
Bernie
Just check with your caravan maker, that the fridge is wired direct to caravan 12v battery.
Some manufactuers wire them up to a relay that is only activated when the tow vehicle has the engine running.
If you stop on the road the fridge stops as well.
If it is a dometic fridge they pull 14.5 amps 12v all the time.
Number 1 in mine I have the second isolator, so it starts charging when the volts get high enough, and shuts down when volts drop.

[berniebgf Senior Member Find all posts View Profile Close berniebgf]

Thanks Charlie,

Your information helps allot, I'll run it past the caravan mob. if I don't have to get the isolator I keep ~$45 in my pocket.

Do you have a breaker / Fuse on yours? and if so what rating?

thanks

Bernie

[cmilton54 Find all posts View Profile Close cmilton54]

Hi Bernie

Yes I have a manual reset 50amp cuircuit breaker.
If I am not using the anderson plug I leave it open cuircuit, if needed just set to use.
Reason for manual breaker was dont have to worry about fuses, and covers fused or damaged wiring in event of accident.

[seenthelight Junior Member Find all posts View Profile Close seenthelight]

Hi Bernie
1. Is the second isolator warranted? (I believe it is) .
I do not run a second isolator because the solar on the van chargers the two batterys while I'm stopped
and when at a caravan park the 240v charger in the van chargers the both the batterys.
2. Is the Breaker warranted? (Answer is Yes for me)
Al so yes to me, one close to the second battery in the car and one close to the batters in the van,
I do not run a diode in the circuit because this would stop the charge to my battery in the car when stopped.
I think a 12v motion switch is better to stop the fridge when stopped
Cheers
Geoff

[snapper49 Member Find all posts View Profile Close snapper49]

First of all
Caravan fridge should not be wired to the caravan battery
It should be wired to run through either the bottom row on a 12 pin plug or an Anderson and run off of the cars main battery
A fridge switch should be installed so that it only runs when the cars engine is running
http://rvelectronics.com.au/index.ph...tegory&path=57
This will protect the main battery
The fridge should be either on gas or 240 volt when stopped and 12 volt when travelling

If you want a charging system off of the car for the caravan battery you wont do better that a ctek dc/dc charger

Run a dual 6mm cable to an Anderson plug and connect through charger to the van battery
You can aslo connect solar panels to the ctek
http://www.ctekbatterychargers.com.a...FahMpgodWU4Apg

No connection to either company just good products

[berniebgf Senior Member Find all posts View Profile Close berniebgf]

Thanks for all of the advice,

I am waiting on a response from the caravan company about the configuration they have so I can adjust my setup to suite.

Thanks seenthelight and Snapper, I like the idea of the "Fridge switch" and did not know that type of device was available. So will look into that depending on info back from caravan mob.

Snapper, I am using the 6B&S plugs with appropriate wiring.. = 13.5 mm sq. So all good there

Bernie

[berniebgf Senior Member Find all posts View Profile Close berniebgf]

Ok, word from Caravan Joint is as follows.

1. Anderson Plug is connected to Battery in caravan
2. Fridge is NOT connected to anderson Plug or Battery
3. Fridge is wired to Pin 8 of the Trailer Plug and is protected by relay from Pin 12 which is Ignition sense.

So I have to make sure power to Pin 8 is correct (Core size) and check that Pint 12 V+ is on Ignition source.

I'm still going to run an Anderson plug with a breaker but may skip the isolator I think..... although any issues have my secondary (which is a Crank battery not Deep Cycle) connected to the caravan deep cycle battery without some "intelligent" isolator or charging device? DC-DC smart charger?

Would like to still be able to use the Anderson plug at the rear to attach solar, light or compressor when I need it, isolator or DC-DC might effect this..

Feedback appreciated.

Thanks

Bernie.

Bernie

[snapper49 Member Find all posts View Profile Close snapper49]

I'm still going to run an Anderson plug with a breaker but may skip the isolator I think..... although any issues have my secondary (which is a Crank battery not Deep Cycle) connected to the caravan deep cycle battery without some "intelligent" isolator or charging device? DC-DC smart charger?

Would like to still be able to use the Anderson plug at the rear to attach solar, light or compressor when I need it, isolator or DC-DC might effect this

If you do what I suggested you wont have any problems (mine up and running and done 13000k with no problems)

From your main battery run a dual core 6mm cable to an Anderson on the back of the prado with an inline 50amp fuse or a circuit breaker
On the van from the connecting Anderson run same cable to your battery on the van
As close as possible to the van battery mount a ctek dc/dc charger links supplied above
through this connect your power source and the van battery
It will keep you AGM Deep cycle fully charged not like running off of the alternator
The charger also has provision for connecting a solar set up through the same charger
Just use another lead with Anderson on the end and connect to the appropriate terminals on the ctek
Its a self managing system and well worth the dollars

[berniebgf Senior Member Find all posts View Profile Close berniebgf]

Thanks Snapper, agree with your setup.

I'll have to go back and ask what (if any) DC-DC management is integrated already between the Anderson plug and the caravan battery, just don't want to double up on devices if something is "in-built".

I do plan on putting in solar and will need a regulator for it, so this information all has an influence on what I purchase. As you said I can get a Ctek to do both Solar and DC-DC charging.

At least now with your advice I can proceed with installing the cabling / breaker / Anderson plug, thanks.

Bernie.

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

You only need to install an another isolator between the cars cranking battery and the caravan if you wish to isolate the vans battery from the the car when the alternators not charging.

You could instead just wire directly to the aux, effectively paralleling the car aux and the van battery and have the combined capacity of the batteries available to both the car and the van, depending on how you want to setup to work.

I assume your already running a booster diode so wouldn't bother with a DCDC charger unless you find you can't get a suitable charge voltage at the van's battery.

Cheers,

Leigh

[snapper49 Member Find all posts View Profile Close snapper49]

Don't need an isolator if you use the dc dc ctek as it does its own isolating ie if no engine running it will detect that and shut down
There is a manual on the link I posted download it and read it

[berniebgf Senior Member Find all posts View Profile Close berniebgf]

True leigh, running the booster.

Only issue is if I run a isolator then I can't use the rear plug for accessories when the car is off... Unless I wire in the bridge function to another switch on the dash.

Let see what comes back from the Caravan mob regarding existing DC-DC setup for battery.

Bernie.

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

Normally you would just have the isolator between the cranking battery and the aux in the car. The aux would be wired away to an anderson plug that would connect to the caravan battery, you would then have power on the anderson plug all the time? Leigh

[MidLifeCrisis Out of control poster! Find all posts View Profile Close MidLifeCrisis]

I have two batteries in the Prado and a trickle charge via an Anderson plug to the camper battery (Projector). Basically the Redarc manages charging between the two car batteries and the projector allows charge to the camper battery once the main start battery is done. (Well thats what Im told). I also run power to the rear of the rig via a separate 6b&S feed to an anderson and multiple other outlets, all from the second battery. this is because the trickle charge will NOT run any items, just charge the camper battery.

It all works very well and in an emergency i can crank from any of them. I.e a switch from the Redarc unit allows me to do it from inside the car and a switch on the projector unit allows me to do it under the bonnet.

mlc