High Amp Wiring - Fridge and other Accessories.

Submitted: Saturday, Jan 08, 2011 at 20:38
ThreadID: 83526 Views:6396 Replies:9 FollowUps:9
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Hi everyone.

I have been scouring through the archives trying to find a few answers to some of my questions. I didn't find what I was after so I thought I would ask before I buggered something up.

I have a Suzuki Grand Vitara that we used to tow our little 6x4 canopied trailer with all our camp kit in it. We are at the point where we want to power our fridge, either in the back of the car, or possibly in the trailer. We have a Bushman Fridge that is a few years old and works like a charm and in our old Patrol I had a Dual Battery set up and heavy gauge wiring already fitted to the rear and that worked great. Now with the new Lil Truck, I want to setup so that I can, as I mentioned, run the fridge either in the back of the car or in the trailer, and also some lighting in the trailer.

What I want to know is..

1- are there any considerations I need to have for the Engine Management Computer in the car. I have heard al sorts of storied about jump starting and causing computer issues, so I don't want to compromise my Lil Truck.

2- I also read that most of the wiring methods indicate that the High Load wiring is run through a relay so that it is only powered when the ignition is on. Is this necessary ?

3- Does any one know what sort of load is drawn by a Bushman Fridge ?

I look forward to any answers.

Cheers.

Gavin.
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Reply By: Member - Phil G (SA) - Saturday, Jan 08, 2011 at 20:49

Saturday, Jan 08, 2011 at 20:49
#1 I haven't heard of a fridge upsetting the ECU and can't see why it would.
#2 No need for a relay, just a fused lead from your battery.
#3 3.8 amps when cycling (info from website)
AnswerID: 441158

Follow Up By: BigGav - Saturday, Jan 08, 2011 at 21:05

Saturday, Jan 08, 2011 at 21:05
Thanks Phil. I was looking on the Bushman website and even looked at that particular page and didnt see it.. Must be getting old..

Cheers.
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Follow Up By: Member - Phil G (SA) - Saturday, Jan 08, 2011 at 22:52

Saturday, Jan 08, 2011 at 22:52
Hehe ...yeah it wasn't easy to find.
For that sort of wiring, I use the tinned 6mm twin sheath cable from Whitworths - its got heaps in reserve for a fridge circuit and is well protected. Whitworths twin sheath wire
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Reply By: Member - The Bushwhackers -NSW - Saturday, Jan 08, 2011 at 21:04

Saturday, Jan 08, 2011 at 21:04
Hi BigGav

I can't help you directly, but there is a good blog on here by John and Val

Click Here

Also, if you click on the Articles tab near the top of this page, there is one article on Power & Electrics.

Hope one (or both) of these assist you,

Cheers, Dave

AnswerID: 441160

Follow Up By: BigGav - Saturday, Jan 08, 2011 at 21:39

Saturday, Jan 08, 2011 at 21:39
Thanks Dave. I have actually had a look at these and they are excellent. My main concern was the ECU, and I have now been told that there should not be a problem. I guess as long as everything is fused properly.

Cheers.

Gav
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Reply By: Ruffy-Dan - Saturday, Jan 08, 2011 at 21:06

Saturday, Jan 08, 2011 at 21:06
I think you'll find the reason for the relay talk is for if you don't have a dual battery system so you don't drain the start battery.

You'd want to run atleast 4mm cable for the fridge and potentially a light or something.

Dan
AnswerID: 441161

Reply By: Member - Graham H (QLD) - Saturday, Jan 08, 2011 at 21:39

Saturday, Jan 08, 2011 at 21:39
If your fridge is in the car you can buy a RAPS 12 unit from Waeco which has a switch that allows you to run the fridege all the time or just when ignition is on. comes with 6 m of wiring so just has to be fitted.

The switch from ignition is usually taken ogg the windscrren wiper wiring.

See here

Raps 12


They are around $112
AnswerID: 441165

Follow Up By: BigGav - Wednesday, Jan 26, 2011 at 11:35

Wednesday, Jan 26, 2011 at 11:35
Thanks Graham H. That looks like a simple solution, and cheap enough to try for starters.

Gav
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Reply By: KenInPerth - Sunday, Jan 09, 2011 at 00:30

Sunday, Jan 09, 2011 at 00:30
Hi Big Gav

Looks like most people have answered your question and the RAPS 12 sounds like a good idea.

The only point I would throw up for consideration, and there will be some people out there with real life experience I am sure, is that if you had a dual battery set up before and are expecting to run the fridge off your (only) cranking battery in the Vitara without the engine running (as in when you are parked) you may not get the same run time and/or may compromise your cranking battery.

Hopefully someone can throw some better light on this than I can - if it is even a consideration

Ken
AnswerID: 441183

Follow Up By: Bonz (Vic) - Sunday, Jan 09, 2011 at 10:41

Sunday, Jan 09, 2011 at 10:41
Yep hence the discussion about a relay. This will sense the battery voltage and cut out protecting the craker. If only one battery I would go a relay and a circuit breaker or fuse int he line. Also wouldnt run anything less than 10mm2, 6mm2 will do it but 10 is better
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Reply By: kcandco - Sunday, Jan 09, 2011 at 04:44

Sunday, Jan 09, 2011 at 04:44
Hi Gavin
I have a bushman fridge in the back of my pajero. According to multimeter it uses 4.2A per hour when running. Over a 24 hr period it runs between 6 and 10 hours depending on temp setting and ambient temp. On these figures power consumption is 25 to 42 Amp/hrs per day. Because of this I definitely recommend a dual battery set up with the fridge running from the aux. It has been a great fridge apart from some trouble when i had a bad connection where plug was going into fridge. It was causing voltage drop and fridge was cutting out. I hardwired the power lead into the fridge and have not looked back. I usually run at between +3 and -3 depending on how cold I want the drinks. I also installed an hour meter (from ebay $20) so I can monitor the run time of the fridge. This has proved really handy for calculating power consumption. It is wired to the compressor supply so it only runs when the compressor is on.

regards Kc
AnswerID: 441187

Reply By: paulnsw - Sunday, Jan 09, 2011 at 09:09

Sunday, Jan 09, 2011 at 09:09
If you want a quality setup that importantly works and fully charges your battery use a Ctek D250S or D250S DUAL which incorporates a solar regulator.
Use a 100Ah or 120Ah deep cycle AGM battery.
All you do is hook two wires from your main start battery to the Ctek D250S and two wires from the Ctek D250S to your battery. Nothing else needed. The battery isolator is included in the Ctek D250S. This is the only method to satisfactorily fully charge and maintain your auxiliary battery.
Suggest you look to the D250S Dual if you ever want to add solar, or best option to maintain battery at home is with 20W solar panel connected to the D250S Dual.
AnswerID: 441203

Reply By: anglepole - Sunday, Jan 09, 2011 at 10:09

Sunday, Jan 09, 2011 at 10:09
Hi Gavin,

The best way to run accessories from an Auxiliary battery is to run both wires (positive and negative) fused on the positive; directly to the battery.

Nearly all manufacturers of CB Radios, Fridges HF Radios and so on, recommend this.

It is cheaper and often easier to use the vehicle chassis as the negative return, this should always be resisted.

Cheers
AnswerID: 441219

Reply By: Sand Man (SA) - Sunday, Jan 09, 2011 at 10:12

Sunday, Jan 09, 2011 at 10:12
Gavin,

If you are not installing an auxiliary battery I would strongly recommend you include a low voltage cutout device in the circuit to the fridge.
Waeco are the only fridges I know of that have a built-in cutout to protect your battery from running flat.

The better solution is to install a portable power pack in the rear of your vehicle to run your fridge from.

ABR Flyer is an excellent solution to suit your needs both now and for future expansion, such as running to a camper trailer, etc.

The flyer comes complete with wiring, built-in isolator etc. to provide a great solution. The only other requirement is an AGM (non spillable) deep cycle battery to put in the box.

I would not run a fridge such as the Bushman off the starting battey, at least without a cutout device to protect the battery from excessive drain.

I have no interests with Derek at ABR apart from being a satisfied customer.

ABR also have a Battery Protector for a good price, although I changed the plug and socket over to a "Merit" style solution which I think is superior to a "standard" cigarette type plug and socket.

Bill.
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AnswerID: 441220

Follow Up By: Member - Phil G (SA) - Sunday, Jan 09, 2011 at 12:22

Sunday, Jan 09, 2011 at 12:22
Gday Bill,
From the Bushman website:
"Battery protection to prevent excessive discharge. The unit is designed to cut out if battery output falls between 10-11V. Cut In/ Cut Out voltages can be varied upon request to suit customer needs. "

Cheers
Phil
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Follow Up By: Sand Man (SA) - Monday, Jan 10, 2011 at 07:02

Monday, Jan 10, 2011 at 07:02
Hey there Phil,

Good info mate, although 11 volts cut out sounds too low. The battery is getting too flat and if is your sole one, may not start the vehicle.
Bushman would definitely need to adjust the voltage up a bit IMO.
11.6v is regarded as most suitable cut out voltage, which still leaves the battery level at 30% or there abouts.


Bill.
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Follow Up By: Member - Phil G (SA) - Monday, Jan 10, 2011 at 18:34

Monday, Jan 10, 2011 at 18:34
Gday Bill,
Yeah, they set it low so its unlikely to do the Waeco thing and cut out because of voltage drop on standard thin vehicle wiring.

Cheers
phil
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Follow Up By: BigGav - Wednesday, Jan 26, 2011 at 11:45

Wednesday, Jan 26, 2011 at 11:45
Thanks everyone for your info. Running off of the ONLY / Cranking battery is a short term option, so I will be looking for a secondary battery at some time in the future. All I am after is the ability to keep power up to the fridge, mostly whilst driving, and for short term / overnight stays. So I will suck it and see how it goes.

Cheers everyone.
and Happy Camping.
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