Caravan Connection - power

[stelz Lurker Find all posts View Profile Close stelz]

Hi fellas,

We have recently got hold of a pop-top van (off-road Jayco expanda with fridge and 2 batteries) and petrol prado (I currently don't have dual batteries in the Prado). The van has the 12-pin flat plug so I need to change the standard 7-pin one over for a 12-pin socket on the back of the prado. I've worked out how to install our prodigy and am just left to work out how to do the power to the van via the bigger pins (5 lower ones).

I think the fridge is wired to pin 9 and pin 8 for charging the van batteries (pin 10 earth). I've had the ford falcon connected and I beleive it all worked. I am fairly sure the falcon would not have a battery isolator and just fuses for both pin 8 nad 9 power feeds.

So, there are a few options:

1) Add a autoreset CB feed to pin 8 to charge van while travelling and leave the fridge to run off the van batteries.
2) wire pin 8 as above, plus a second feed to 9 with resetable CB
3) Install isolator in Prado and run one feed to pin 8 as above and jumper supply to pin 9 as well

I'm not sure what the isolator would do for me though.

I wondered if it would be ok in options 1 and 2 to run pin 8 off a supply which is only active when the engine is running and pin 9 off the accessory key switch position.

Please help as I am a newbie and would like to avoid the pitfalls.

Thanks,
Stelz

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

Hi Stelz

An isolator is used to separate batteries, In its simplist form it is just a switch, next step is a relay, so that electronics can control when the batteries are connect or diconnected. It is used so that you can run accessories from the 2nd battery without discharging the main (starting) battery.

I wondered if it would be ok in options 1 and 2 to run pin 8 off a supply which is only active when the engine is running and pin 9 off the accessory key switch position.

The inteligent isolators will only connect once the car is running and the start battery has charged to a preset level. This is the best way to achive the connect when engine running function.

The main problem that I see with your current setup, is the voltage drop from the long run of cable and the small sized connector in the trailer plug. This increases the resistance, and as the name suggests this restricts the current flow. This will cause the fridge to be less efficient, and the trailer batteries will take longer to charge (meaning they may not be fully charged).

My suggestion if planning descent trips would be to install and isolator in the prado, then HD cable to the back, then using Anderson type connectors, continue the HD cable to the trailer batteries, effectively using them as your aux batt. You can then simply run the fridge continually off the trailer batteries.

This will not be the cheapest option but certainly the best IMO.

Matt

[leachy_9 Advanced Member Find all posts View Profile Close leachy_9]

Stelz,

My advise is do not use auto reset circuit breakers, use a fuses or a quality manual reset circuit breakers.

I don't know what the current rating of your 12 pin plug is, or what charge control equipment is in the van but I would suspect the max. charging current of th evan batteries may be beyond the rating of the 12 pin plug. Likewise just taping off an existing accessories circuit in the Prado is likely to overload that circuit.

Given the limited info. I'd suggest the best solution is to install a dual battery isolator (Redarc or similar). From this cable (via a resetable circuit breaker or fuse) to a 50Amp Anderson plug at the rear of the Prado (10mm2 twin cable). Then plug what ever battery charge controller the van has into the Anderson plug. The fridge should be powered directly from the battery (via a fuse) in the van.

Again I don't know what battery charge controller is the van, but if you have a D4D, the van will require some type of voltage boost device (RanOX or Arrid twin charge etc.) in order to achieve a 100% state of charge in the van batteries.

If you can be more exact with what is in the van I can give you more definite answers.

Leachy

[stelz Lurker Find all posts View Profile Close stelz]

Thanks for the help so far. Here are further details.

The van has a setec ST20 on board which can have an external DC supply to charge the batteries. Here is an extract of what it says in their manual:

Auxillary Power Input: The power supply terminal “Aux In +VE” provides an alternative option
for powering of the load and float charging of the batteries when mains voltages are not present.
This input is to be powered by a suitable +12V system. (ie CAR). The voltage of the auxilliary
power source should not exceed 14.8 volts.
When operating via the external input, current and voltage control for the battery must be provided
from the external source. The ST20-II/35-II does not provide battery current limit or voltage control
when operating in this configuration. Trickle Charge is still functional when powered through
“Aux In +VE” terminal of power supply.
Suitable fuse protection must be provided for this input. A fuse rating not exceeding 20 Amps for
ST20-II and 30 Amps for ST35-II must be used.


The 5 larger pins in the trailer plug are rated to 35A, while the normal 7 pins are rated at 15A.

Sounds to me that everything should work if I use heavy cable straight from batt (via CB) to pin 8 (not connect pin 9 so the fridge can't be connected directly to the car). I would just need to be careful not to leave the caravan connected without having the car running. It sounds like that is one function that the isolator performs - making sure the car battery is not drained !!!

I wonder how the falcon has been wired ?

[Pedro Advanced Member Find all posts View Profile Close Pedro]

I have a Jayco Freedom with a Fullriver battery in van charged while travelling via heavy duty cable connected by Anderson plugs to vehicle.

It is along same lines as Waltec outlined.

Have the same heavy duty wiring to van fridge which has a "motion sensor" which means fridge does not run off battery when stopped (for about 3 minutes I think).
Even if you ran fridge off car battery this "motion sensor" is probably essential because battery will run down quickly if plug not disconnected when stopping for extended periods.

While doing a search for info on "motion sensor" came across this site which covers a few points you are probably interested in.
http://www.hardingscaravans.com.au/wire.htm

One other thing is that if i want to charge the van battery on 240v I use my Ctek 7000 ( which has an Anderson plug attachment) and plug it into the van Anderson Plug.
That way no need to get to the van battery (stored under seat)

Check out this thread for the adapted Ctek 7000

http://www.pradopoint.com/viewtopic.php?t=617&start=0

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

What you can do is get a horn relay, wire it in line with the heavy cable to the trailer plug. The control coil of the relay supply from an accessory circuit in the prado, that way the relay will only connect to the trailer when you turn the key on. You will also need to wire a 20 amp breaker in to protect the ST-20 from excessive current.

Matt

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

I would recommend a second battery in the car for a start with the appropriate system/isolator to get good charge. If not then the isolator should be used and the van battery would be viewed as the Aux. The Van battery can then run off that. If you are going to charge from the car, then you need some very good cable 6 B&S, and then a good connection to carry the potential current when the system discovers that you battery is flat and then tries to push the amps in. This could be very high for short periods. I have decided to install 175 amp Anderson plugs rather than the 50 amp. It might be over kill but hey! Have you looked at the size of the cable that runs between the first and second battery in a normal installation. What makes you think that the battery cable to the van would be too much smaller? I would recommend a quality 100 amp circuit breaker that runs off the battery to protect the whole dual system as well as those items that then run of the dual battery via a fuse box. This then allows the system to be switched off when necessary. Everything is then covered.

A recommendation has been made to run a horn relay to enable a disconnect when the ignition is off. Better make it a 100 amp relay if you want to do this. Having to disconnect each time you stop the engine/shopping so the fridge doesn't drain the car battery, would be a giant pain in the butt and prone to accidental draining. So so a proper installation and you wont have problems.

I am alittle surprised about the battery charger in the van. It is the same for the Outback Eagles and is only a trickle charger. If a 100 amp/hr battery is used and the battery get down to 50% on a non powered environment, then it would take 62.5 hrs to charge the battery at the .8 amp trickle quoted by Jayco. Impossible! The Ctek charger would be a better charger while at a 240 volt source.

My system is as follows: a Ctek charger permanently installed under the bonnet; a dual battery charged every month or so at home in addition to the normal charging of the dual battery system; a heavy duty cable (6B&S) to the trailer plugs (175amp Anderson) and hence a charging circuit to the trailer battery; extention cords made to plug into the charging circuit to use the Ctek from the car while in camp and having 240 volt available( I cannot leave the car attached as I can't open the rear door if I do!); additional extention cables for charging other batteries via croc plugs.

I have been able to do this very economically by buying plugs from Larrikin products, larpro.com.au and cables from Battery world. I have no affiliation with both of these companies just good experiences.

I hope that this perspective helps. I would be very interested in what you end up doing.

Regards Martin

[MattWhite Advanced Member Find all posts View Profile Close MattWhite]

I am not trying to chase you away but check this out....
http://www.exploroz.com/Forum/Topic/...r_trailer.aspx

Also, I think you'll find you wont need huge cable as the car will power the setec to charge the batteries so you I suspect you'd only be talking 10amp max. I think the setec is the isolator too. Good luck.

[stelz Lurker Find all posts View Profile Close stelz]

I think over the weekend I will have a good look at how the caravan is actually wired from the 12 pin plug to both the battery and the fridge and make some decisions from there. I am not going to be using the van for long periods without mains connection for a while, so might just take the simple option and install a 7-pin plug on the caravan to make the brakes and lights work, install the prodigy. I might run some heavy cable in the car when I run the prodigy cable so I can just make the electrical connections at a latter date once I work out which way to go.

I'll keep you posted as I am not sure how the jayco is wired and the wiring diagram that came with it is crap !!!

Thanks for your help.

Stelz

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

Good idea Stelz. It is better to progress with ease rather than feel pressured and have to do it again when you find a better or safer way. Wiring can be the bane of your life or fun. My old physics teacher told me to view it the same way you do a hose and water. It can simplify it sometimes when you can't get your head around it.

Martin