Wiring up ciggy socket to run a Waeco fridge.

[beretta]

HI all,

Got myself a new Waeco CF-60 for my 30th. Have had it running through an extension into the ciggy lighter in the dash and its awesome, keeps the beers and bourbons icy cold! Probably good for food too?

Anyway I need to wire in a ciggy lighter style socket at the back of the car to run the fridge and a few other things from time to time (compressor, shentai electric rattle gun thingy etc.), so;

1. What I need to know from someone who knows is what size/gauage wire should I run?

2. What size in mm2 is 8 guage? cos I've got some of that left over from wiring up some lights.

2. I will be putting an inline wedge style fuse in also, what voltage should it be?.

I am guessing it will work out to around 6 - 8 meters from my 2nd battery to the position near the rear door of the GQ.

Thanks for the help, much appreciated!

Cheers,

Beretts

[-Scott-]

There are two primary factors to consider: will the wire carry the current without overheating, and what will be the voltage drop?

8 gauge will carry the fridge current without trouble (and a bucketload more, too.) Voltage drop is a different issue - requires calculations, and numbers relating to the wire, so that's too hard right now.

Essentially, bigger is better - larger diameter wire has less resistance, drops less voltage so more is available for your fridge (or whatever.) When you use really large wire it can be difficult to terminate properly.

Your fuse only needs to be 12V - do they come in any other value? Current rating will get a discussion going. Your fuse needs to be large enough to carry the load current, but low enough to blow before the wire melts. Start somewhere between 10 and 25A.

Cheers,

Scott

[spannercrab]

I agree wholeheartedly - 8ga is LOADS big enough for your application.

8ga is 8.36mm2 which is capable of 76amps chassis or 24amps current capacity wiring.

The fuse is there to protect the wiring - if the wire can take it, then make it so. Since your fridge draws around 4amps, 10 is heaps, but you can go any size up to 25A - this is dictated by the smallest size wire in the circuit. If it's 8ga all the way (including the connector from the socket to the fridge), 25A would be no probs ... but again, 10 or 15 would be ample due to the current draw needed by the unit.

You may also wish to consider changing the plug ends to something more substantial than the cig. plug - such as AMP Canon style connectors or the Hella HD DC Plug / sockets. This improves contact area etc and prevents voltage drop through the connectors.

If you are running the fridge on your Aux, and it's capable of discharging to 10.5v limit (normal starter batteries this does not apply to) - you can also change the voltage cutout on the Waeco to "Low" - which allows more to drain from the battery before the fridge turns itself off.

If you are running from the engine bay to the rear of the truck - 8m is way too much ... more like 3-4m maximum .... the shorter you have the cable, the less the voltage drop & the smaller cable which can be used.

For a 4m run, the voltage drop will be 0.05V

For 8m, it will be 0.08V

Either figure is negligable for all intents and purposes, but the shorter the better.

[beretta]

Thanks for the replies people, very helpful! Yeah with the fuse I meant amps not volts, it was kinda late when I wrote it.

As far as distance goes it may end up being more like 4-5meters, but I was estimating 8 as a worst case scenario. I think I will go for a 15amp fuse as in the manual for the fridge it says minimum 15amp for an inline fuse, I was just more concerned about the draw of other items like the compressor etc, would 15 be enough to run most other accessories?

[spannercrab]

How long is a rubber band?

15A would be enough to run up to 150W of accessories from the socket by themselves.

Check the amps draw on your devices - considering 8ga is at least twice the size of standard car wiring - I wouldn't foresee a problem - but if you have something like a Blue Tongue compressor then no way will it run on 8ga from a cig lighter plug (30-40A draw) - if it's a BigW / KMart special, then probably ... but you would need to check the specs sheet on the compressor and anything else you may wish to run.

[Tiny]

connections and plugs on ciggie lighters are not great and tend to burn out with ongoing high amp draw, generally a marrit type (mirine) plug which are the smaller ciggie lighter style plugs are better and you can get them in fluch mount and side mound from hella. We do them if you woant further info. Other than that proper 12v plugs like the plug that is in the back of the weaco fridge is a good option.

[beretta]

Compressor is a Bushranger Max Air, the only other thing I use at the moment is a Shentai Impact gun/wrench or whatever?

I've ordered one of these to install into the rear trim:
http://cgi.ebay.com.au/Power-Socket-4WD ... dZViewItem

Don't know if the price is any good, but I can't get away from work to go buy one!

[beretta]

connections and plugs on ciggie lighters are not great and tend to burn out with ongoing high amp draw, generally a marrit type (mirine) plug which are the smaller ciggie lighter style plugs are better and you can get them in fluch mount and side mound from hella. We do them if you woant further info. Other than that proper 12v plugs like the plug that is in the back of the weaco fridge is a good option.

Thanks TIny I should have checked your website out first dude, would rather buy from you and support people off here, will next time.

[murcod]

Compressor is a Bushranger Max Air, the only other thing I use at the moment is a Shentai Impact gun/wrench or whatever?

I've ordered one of these to install into the rear trim:
http://cgi.ebay.com.au/Power-Socket-4WD ... dZViewItem

You might want to check the current rating on that socket/ plug if you're planning on plugging a Maxair into it- The Maxair's draw a fair amount of current (over 20Amps IIRC?) Personally I would be using the supplied alligator clips and attaching it direct to the battery as over a long cable run you will notice the difference for such a high current drain device.

[RoldIT]

Agreed. MaxAir's will draw upto 30 amps and although your 8ga wiring will take the load regarding heat, the plug may not and you'll get substantial voltage drop causing the compressor to run less than effeciently.

According to my calculations you'll get about .6 of volt drop at the plug using a MaxAir. Any more than .3 of a volt drop is usually considered too much.

[Tiny]

connections and plugs on ciggie lighters are not great and tend to burn out with ongoing high amp draw, generally a marrit type (mirine) plug which are the smaller ciggie lighter style plugs are better and you can get them in fluch mount and side mound from hella. We do them if you woant further info. Other than that proper 12v plugs like the plug that is in the back of the weaco fridge is a good option.

Thanks TIny I should have checked your website out first dude, would rather buy from you and support people off here, will next time.

no stress mate, don't expect anyone to buy off me, but a chance to quote is always appreciated