6mm cable not enough for rear 12v sockets

Bit of a useless post but someone may find this one day on a Google search...lol

I recently set up the dual battery system with the Piranha management box and all that jazz but ran 6mm cable to the rear with some 12v outlets.

Everything works fine except for the fridge kept cutting out (on off, on off). Ran earth straight to chassis and tried earth to negative on battery too but still had same issue.

Ending up being just the cable with voltage drop so keep that in mind when running power. Don't cheap out, get quality 2 B&S RED "SINGLE CORE".

Thanks to Mudrunner for the advice.

Specifications
32.07 mm square nominal area
stranding 399/0.32
188 amp rated @ 30 degrees C

Yep the old voltage drop.
Bit overkill though, 32mm.sq is actually 255A rated.
6mm (4.58sq.mm) 50A rating, should have been fine for your fridge unless you were sharing that same cable with other accessories running at the same time.
Also if your fridge has a Danfoss compressor they can draw up to 20-25 amps on start up but only draw about 5A once running.
6mm cable over 6mts with a 25A draw you can expect about 0.55 volts drop which is too much in a 12V system. You want to keep it under 0.36V drop. Made worse too if your battery is low and other things running as well.
Cheers, Dave

Hi mate yeah I am sharing it with the camper lights, chargers and fridge, etc...

Question for Bordertech

I'm about to put in a 100w HF Codan NGT radio, with the aerial on the bull bar and will probably put in a 3rd battery in to run it, with that battery being located under the pod at the back.

Is 6mm strong enough to go the distance/length (it's not a loaded question for you sick people, either!!)?

Thanks.

Rossco

100 w at 12v = a current draw of 8.3A rosco

Quote:

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Originally Posted by DX grunt

Question for Bordertech

I'm about to put in a 100w HF Codan NGT radio, with the aerial on the bull bar and will probably put in a 3rd battery in to run it, with that battery being located under the pod at the back.

Is 6mm strong enough to go the distance/length (it's not a loaded question for you sick people, either!!)?

Thanks.
Rossco

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Dx grunt, depends on the length of the cable, the longer the length the thicker cable you will need. If you are going from front to back etc I would go atleast to an 8 B&S cable or even go up to the 6 B&S, run it into a fused distribution block and you could run other things off it as well as the HF, just a thought. You will obviously need to charge this 3rd battery as well and if in the back like you said I would use a minimum of 6 B&S. Are you going to join the batteries up into a triple battery setup or have one of the ARK battery boxes with the charger already in it.

Sorry if I have added to the confusion but it can cost a lot of money to fix a stuffup...I know as I have added more wires and taken wires out changed things around and it has cost me a few dollars.

cheers

Greg

Thanks guys.

I was going to run it off the 2nd battery, but seeings I'll be going to some pretty remote spots, I'll need it 'just in case' and want it to have an independent power source.

Charging in the middle of nowhere shouldn't be a problem because I have got 2 x 125w solar panels married up and hasn't let me down yet, but will need it wired into the 3rd battery.

I got told the best option is to turn it off when not in use, because leaving it on scan mode drains the battery pretty quick apparently.

I'd prefer to go the 6 B&S for 'peace of mind' because you rarely get a second chance in the outback.

Thanks again.

Rossco

Quote:

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Originally Posted by gregs

dx grunt, depends on the length of the cable, the longer the length the thicker cable you will need. If you are going from front to back etc i would go atleast to an 8 b&s cable or even go up to the 6 b&s, run it into a fused distribution block and you could run other things off it as well as the hf, just a thought. You will obviously need to charge this 3rd battery as well and if in the back like you said i would use a minimum of 6 b&s. Are you going to join the batteries up into a triple battery setup or have one of the ark battery boxes with the charger already in it.

Sorry if i have added to the confusion but it can cost a lot of money to fix a stuffup...i know as i have added more wires and taken wires out changed things around and it has cost me a few dollars.

Cheers

greg

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6b&s should do the job ,put in fuses and such and should be ok

dont forget you can top up the batteries with your panels as well

Your 100w Codan will draw around 20 amps

Very important lesson here

RF (Radio Frequency) watts and DC watts are two different wots

Is Big, Is Good! Better to over do it than suffer from voltage drop. Sudso does the mathes and I don't doubt the calculations at all. Just a big fan of going large to the back of the car to a distribution fuse box then work it out from there.

7 years ago I was fitting a Big Boss compressor for the back of the car and ran a decent wire but the thing just did not perform to expection. Re ran the wire 3 times bigger each time till I was running BIG stuff and the performance increased each time. Same thing happened to my 80lt weaco when I first got it, on off on off and not cold. Bloody voltage drop.

Go large. Do it once.

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