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White Lightning
16-08-2007, 11:17 AM
What are your opinions on the best size wire for wiring a hella type plug to rear of vehicle. Car is 07 D4d with ARB Dual Battery, Fridge is 50lt Waeco.

I am going to run pos & neg back to aux battery with a fuse in line, just need info on correct size wire as the waeco is fussy on voltage.

On a side note, an auto sparky advised me to connect the positive to the ARB solenoid lug for the aux battery and earth the hella plug at the rear of vehicle somewhere. Said any sized wire will do... Is this correct or BS ??

Piggy
16-08-2007, 02:51 PM
You would be very safe wih a 6mm, no voltage drop in that size from the front of the vehicle.

The Waeco 50ltr draws bugger all current.

You could get away with earthing locally quite comfortably.

xvprado
16-08-2007, 03:17 PM
You would be very safe wih a 6mm, no voltage drop in that size from the front of the vehicle.

The Waeco 50ltr draws bugger all current.

You could get away with earthing locally quite comfortably.

Agreed in total, cept for the earthing
6mm works fine, but make sure it is 6mm2 (squared) as there is lots of confusion on three different standards for cable size

Im a bit anal on earthing, thats why i would earth back at the battery but hey, lotsa people agree with TP and Im probably in the minority
lots of good info at <removed due to spam content> on this stuff

White Lightning
16-08-2007, 04:31 PM
I've got some "narva' brand cable. Red & black cables inside a black sheath. Says 6mm' or 4.58mm.

I assume this is ok

starcees
19-08-2007, 11:41 AM
Hi all,

I have just been through this exercise so I thought I would write my results. I have a dual batt installed now, I have run 4mm2 wire from batt too rear socket, earth using factory earth. Testing the system these were my results; Engel 60L (running) has a voltage drop of 0.3 volts, the fridge draws 2.5amps. All within acceptable limits. Just for general info I purchased the new engel yesterday replacing a 25 year old one. The old one was a 21 litre and it draws 4.9 amps at 12.26 volts. Thought you guys would be interested, my wife certainly isn't!.

P1
19-08-2007, 12:21 PM
Im a bit anal on earthing, thats why i would earth back at the battery but hey, lotsa people agree with TP and Im probably in the minority
lots of good info at <removed due to spam content> on this stuff

XV, there seems to be a problem with the link. It just goes to a commercial ad link site. :cry:

xvprado
19-08-2007, 12:41 PM
Im a bit anal on earthing, thats why i would earth back at the battery but hey, lotsa people agree with TP and Im probably in the minority
lots of good info at <removed due to spam content> on this stuff

XV, there seems to be a problem with the link. It just goes to a commercial ad link site. :cry:


woops www.campertrailers.org (http://www.campertrailers.org)

orangepeel
20-08-2007, 08:30 AM
whats the best type of plug for the rear power ?

I am about to install a 60L engel from the dual battery - but i am wanting to make sure the rear access does not keep loosing power to the fridge (from vibration) - the power lead falling out.

I hear Hella plugs are good - and some anderson plugs?

What about the standard engel socket?

What is everyones setup for plugs ?

Just*Managing
20-08-2007, 09:01 AM
I went for Hella on the recommendation of the sparkie. I'd heard quite a bit of talk about Andersen but whilst he thought Hella was better, couldn't give me a real reason why. I have always been annoyed about the standard socket on my Waeco sometimes losing connection in the Transformer or my Battery pack so while I was at it, i replaced both of those with Hella too (leaving one standard plug in the battery pack). Works brilliant, no more accidental warm beers :lol:

Jacto
21-08-2007, 11:21 PM
My 2 cents worth :)

When I bought the bushman fridge, the electrician recommended 6mm wire so there would be bugger all voltage drop to the rear of the vehicle

Drew
22-08-2007, 12:13 PM
Voltage drop can be easily calculated.

Vd = (RxIxL)/A

Where:
Vd = voltage drop in volts
R = Resistance per metre in Ohms - use 0.017 for copper.
I = Expected peak current (where the highest voltage drop will occur)
L = Total Circuit length. (Double the run distance to account for each conductor. Suitable also for chassis return calculations, provided your earthing is sufficient (this is the difficult part to get right and this is why some people shy away from using a chassis return)).
A = Cross Sectional Area of the cable in mm˛. Note: 6mm auto cable is 4.59mm˛. See www.tycab.com.au (http://www.tycab.com.au) or another cable manufacturer for their CSA figures. Do not use the generic description. 6mm auto is not 6mm˛!

So if it's 5 metres of cable run to the back of your truck, and your fridge draws about 3.5 amps (a good average) and using 6mm auto cable, then the calcs work out thus:

Vd = (R.I.L)/A
=(0.017x3.5x(2x5))/4.59
=0.129V

That's 129mV - meaning if your engine was off and your aux battery was putting out 12.4V - there would be 12.27V at the socket. Once you add a bit of resistance across connectors and stuff this might be as low as 12.1V. Still plenty enough to safely run the fridge without it cutting out. AFAIK, most fridges cut out at roughly 11.5V.

Hope this helps somewhat. Fire away with any questions if anything isn't clear.

Drew.

Drew
22-08-2007, 12:18 PM
whats the best type of plug for the rear power ?

I am about to install a 60L engel from the dual battery - but i am wanting to make sure the rear access does not keep loosing power to the fridge (from vibration) - the power lead falling out.

I hear Hella plugs are good - and some anderson plugs?

What about the standard engel socket?

What is everyones setup for plugs ?

I plan to use Clipsal "T" plugs. They look very similar to a standard 240V appliance plug, only they have a different plug pattern. They are the plugs recommended by the Australian Standards. The main reason I plan to use these it that I've got a few of them lying around from a previous life! Hella plugs are also good, I've used them in installs many times and they perform remarkably well.

Good luck,

Drew.