Caravan 12v System

Joined: 05 Dec 2003 Location: Brisbane Australia

hi,

my brother's both baught a caravan each and they want to have a seperate battery system installed on them.

it will be mounted on the chazzy under the van in a weatherproof container (to be made from steel)

we are thinking 2 large deep cycle batteries and a large charger permanently mounted with the batteries.

we went to see an auto elec re: charging from the car, but the run from battery to van batteries is nearly 12 metres. The auto elec said the cable would have to be stupidly big to get charge to the van batteries, and even then youd probably only get 3-5 amps which could take yearts to charge them Smile

so basically we are looking for a self sufficient setup.

the chargers we have looked at are 15amp long service chargers with many bells and shistles and are priced at about $500.

just wanting some input into what charger to get, what batteries to get etc.

i may go see a forklift mob as they often have large charger/battery systems on the electric pallet jacks (they do at work anyway).

any advice is appreciated

Joined: 30 Dec 2002 Location: Adelaide

Something like the Dick Smith / Jaycar dual battery controller kit would be perfect for a caravan set up. It requires a small amount of resistance to be in the aux battery line for it to function correctly- so a long cable run is essential for it to work properly. All up maximum charge current is only around 30 amps.

Joined: 05 Dec 2003 Location: Brisbane Australia

murcod wrote:

Something like the Dick Smith / Jaycar dual battery controller kit would be perfect for a caravan set up. It requires a small amount of resistance to be in the aux battery line for it to function correctly- so a long cable run is essential for it to work properly. All up maximum charge current is only around 30 amps.

hmmm, as i said i dont think its possible to pull 30 amps along 12 metres of wire

plus an earth wiure back to the vehicle aswell.

really only looking at the system being self sufficient, ie fixed mains power charger, ie when the van is plugged into 240 the batteries also charge

Joined: 21 Oct 2003 Location: North East Melbourne

dont know if you wanted a cheap solution or not, but what about solar panels. self sufficient. but have the car charging option still available aswell.

Joined: 30 Dec 2002 Location: Adelaide

Shadow wrote:

murcod wrote:

Something like the Dick Smith / Jaycar dual battery controller kit would be perfect for a caravan set up. It requires a small amount of resistance to be in the aux battery line for it to function correctly- so a long cable run is essential for it to work properly. All up maximum charge current is only around 30 amps.

hmmm, as i said i dont think its possible to pull 30 amps along 12 metres of wire

plus an earth wiure back to the vehicle aswell.

really only looking at the system being self sufficient, ie fixed mains power charger, ie when the van is plugged into 240 the batteries also charge

I was thinking of it more as another addition, for when you can't get to a 240V outlet. Your cable wouldn't have to be that thick to handle 30 amps over 12m (remember I said the charging circuit requires some resistance in the aux line).

Joined: 05 Dec 2003 Location: Brisbane Australia

well the vans will also be towed by my father at some stage so we dont really wanna have to wire up every car thats gonna tow it. rather have the van self sufficient.

mainly looking for advice on choise of battery and charger guys. we are pretty happy with the solution we have, just want the best batteries and chargers for the job.

Joined: 20 Feb 2004 Location: Melbourne

Ive done a similar thing to this on my dads caravan as well. In the end i used some 8mm cable just for the charging lead for the battery, and then looked around for the best quality 7 pin socket i could find. I ended up using a Narva truck type 7 pin plug and socket which is designed to take large size cable. I figured that on something like a road-train, there would be a fair amount of current draw due to the amount of lights and they mostly use 7pin plugs so it should work.....

The caravan battery gets its feed from the vehicle charging system via a solenoid and blade type in-line fuse. When the ignition is switched off, the solenoid turns off, isolating the caravan battery. The caravan battery is mounted in a boat type battery box on the draw-bar.
The set-up works really well and so-far hasnt given them any problems.

Nick

Joined: 05 Dec 2003 Location: Brisbane Australia

we ended up going for a self maintained system with 2 Big 6v batteries and a 15amp Smart Charger.

This means that the batteries charge whenever the van is plugged into 240v, which is pretty much alot since they have a generator aswell.

An auto elec made up the cables for us and we mounted the system insed the van (under the main bed) in a sealed enclosure with a vent to external air.

seems to be working very well atm, the charger draws about 1amp when its pushing about 10amp into the batteries so the generators should have no problem running them aswell as other things in the van.

Joined: 16 Jan 2004 Location: WA

hope the system you have decided on works well...

i will throw this link into the thread anyway, which shows how you could wire up your caravan/boat for 12V from the host vehicle...

http://www.aroundoz.com/diy_archive/fridge_car_wiring.htm

Joined: 31 Mar 2003 Location: Brisbane or 169.254.243.241

the_smoo wrote:

hope the system you have decided on works well...

i will throw this link into the thread anyway, which shows how you could wire up your caravan/boat for 12V from the host vehicle...

http://www.aroundoz.com/diy_archive/fridge_car_wiring.htm

That was a good write up, the only thing I didn't like was there were
no plastic sheaths on the relay spade connectors, could earth out on the number plate after a small shopping centre style incident, I know the breaker would trip out but it would be a pita if that stopped you fridge working and spoiled food

Tom

Joined: 16 Jan 2004 Location: WA

yeah... wouldnt hurt to cover each connector in heatshrink. costs bugger all. makes it a bugger to measure from each terminal when fault finding tho....

Joined: 31 Mar 2003 Location: Brisbane or 169.254.243.241

the_smoo wrote:

yeah... wouldnt hurt to cover each connector in heatshrink. costs bugger all. makes it a bugger to measure from each terminal when fault finding tho....

you can ge the clear plastic ones that slide over the ends which are thick and insulate well, I have them, will get you a photo if you like
you can slide them down to troubleshoot

Tom

Joined: 16 Jan 2004 Location: WA

i know the ones you mean...the nice soft ones.... they are good...

Joined: 30 Dec 2002 Location: Adelaide

The "diac" relay is overkill for this type of install. They're designed to protect active devices (eg. transistors) when they're used to switch the relay. In that case not necessary. Wink