12 volt wiring - a primer for a beginner (idiot? ;))

Gaelic
Reg. Apr 2006

Posted 2006-11-09 4:54 PM (#51310)
Subject: 12 volt wiring - a primer for a beginner (idiot? ;))

Regular

Posts: 63

Location: Canada

Can anyone help me with this? I've done a search and either the answers I find are too in depth or don't address what I'm looking for.

I want to be able to run my interior lights off of a marine battery at shows. We will be camping in our trailer, and don't want to drain the truck's battery, so want to have the lights separate.

How do I do this? I have a diagram showing the positive and negative parts of the battery, leading to a fuse box, leading to the switches, leading to the lights themselves. Where do I buy the supplies? What supplies do I need? We will have about 5-6 LED lights (hopefully!) in the LQ and maybe 2-3 dome types in the horse section. Very simple.

Can someone explain this to me, an idiot? :)

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maccwall
Reg. May 2004

Posted 2006-11-09 6:33 PM (#51314 - in reply to #51310)
Subject: RE: 12 volt wiring - a primer for a beginner (idiot? ;))

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Posts: 524
500

Location: Lone Oak, Tx

HI Gaelic,

It's really fairly simple once you get the idea but I understand not having that idea at first. Been there done that. Batteries I used are Marine batteries that I bought at Wal-Mart, 2 group 24 batteries (don't ask the Walmart people what that is cause they usually don't have a clue). Fuse block and lights I bought on Ebay. I used 4 awg wire (bought at Home Depot) to connect my batteries together and 8 awg wire to run to my ground from the batteries and fuse block and the positive to my fuse block from the batteries. You want to try to keep the fuse block within at least 10 feet of your batteries. The closer, the better or you'll have to use larger wire to connect to the fuse block. From the fuse block you can run your wiring to your lights. I would use 12 awg wire for that and suggest using loom to run your wiring through. Figure out what amperage your lights are total (if you have more than one hooked up to one outlet) and that's the size fuse you'll use for that circuit. I think my fuse block has 10 slots for fuses and the fuses are the blade type automotive fuses. I have not used all the the slots and probably won't but if I need them they are there. Make sure the fuse block you get has a ogunding strip.
It's not very difficult once you understand what's going on. I would also suggest getting a fuse for the line off the battery to the fuse block and put that as close to the positive battery terminal as possible.
You can check my website on the electrical page if you want to see some pictures and a description of how I did mine.
Hope this helps.

Edited by maccwall 2006-11-09 6:39 PM

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Gaelic
Reg. Apr 2006

Posted 2006-11-09 8:15 PM (#51318 - in reply to #51310)
Subject: RE: 12 volt wiring - a primer for a beginner (idiot? ;))

Regular

Posts: 63

Location: Canada

Thanks! I'm going to try to make sense of it all :)

Can I just use one fuse for each light and keep it simple? As I said, I don't want many, or will that just cause too many wires? I was going to put the battery just under the gooseneck, and the fuse panel on the inside on the inside wall, just under the gooseneck, so there will be little distance between the two. So then run wiring from each fuse to each light - or is that wrong? Sorry, I'm still trying to sort this out in my head.

I'm going to buy the battery (I think I only need one - won't run them much) from a place here called Canadian Tire. I'm sure Walmart wouldn't have a clue, and neither do I :)

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10Ha.Wood
Reg. Jun 2006

Posted 2006-11-14 9:07 AM (#51453 - in reply to #51310)
Subject: RE: 12 volt wiring - a primer for a beginner (idiot? ;))

Member

Posts: 46

Location: Ottawa, ON

Gaelic,

In a nutshell:

Everything negative connects to the metal frame of the trailer.

Put a large fuse (50A or so) very close to the positive terminal of the battery, preferably less than 6 inches from the terminal and inside the battery box.

Include a disconnect on the trailer battery, so that you can 'isolate' it. If something goes wrong with this battery you will want to be able to disconnect it quickly and easily.

Run a large (small gauge) wire from the large fuse to your fuse/distribution panel. From the fuse panel you 'distribute' the positive by running smaller wires to your lights and other accessories. LEDs draw so little current that you will be able to put them all on a single fuse.

I just finished this on my trailer - well not quite, I have yet to install the LED lights, but that is a small job.

I mounted the battery under the goose, on the bulkhead wall, over the spare. I also built my own fuse / switchbox that is mounted on the inside wall a foot or two from the battery. The fusebox is connected to both the battery and a new trailer plug mounted under the goosneck. This allows me unplug the trailer from the truck and plug it into "itself".

When I plug the trailer into itself, the battery can be used to power all the lights, including the running lights and the 'hazard' flashers. In an emergency, I could unhook the truck and leave the trailer with it's flashers going and marker lights on.

I also made my own LED lights on the cheap by buying high intensity LEDs on ebay and hacking cheap dome light fixtures. I set up my LED lights on two way switches and have a dimmer at the head of the gooseneck.

If you like, I could take some pictures so you can see how I did it. Feel free to contact me directly for advice and local resources. (for example, Princess Auto had 12V 13watt fluorescent lamps on sale a couple of weeks ago for under $9. The one here in Ottawa still had lots left over at the sale price a few days ago)

Chris

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10Ha.Wood
Reg. Jun 2006

Posted 2006-11-15 8:49 AM (#51515 - in reply to #51453)
Subject: RE: 12 volt wiring - a primer for a beginner (idiot? ;))

Member

Posts: 46

Location: Ottawa, ON

Pictures are here:

http://smg.photobucket.com/albums/v738/10HaWood/Trailer/

The LEDlights pictures show my homemade light fixtures as well as the two way switch and dimmer that will go at the head of the gooseneck. This box will also have an extra 12V outlet.

The Battery pic shows the battery box sitting on a frame that I welded up and bolted to the trailer. You can also see the new plug with the trailer 'plugged into itself'. Inside the plastic battery box is a disconnect and an in-line 50A fuse.

The electrical box pic shows my homemade power distribution/fuse/control box. It has a Lexan cover that allows you to see what is inside. At the top left is the terminal block where the new trailer outlet connects. Immediately under that is a flasher that blinks the hazard lights. The three silver switches activate the hazard lights, the marker lights, and disable the reverse lights. (my truck uses pin 7 for reverse lights, this switch allows me to turn them off if I ever hook the trailer to a truck where pin 7 is hot) Bottom left is a voltmeter that shows the voltage on the battery. At the top right is the fuse block that distributes the power to the individual circuits. Under the fuses you can see the first couple of light switches and two 12v power outlets.

This project would probably seem a little over the top to some, but hey, I scrounged most of the parts, and had a blast figuring it all out!

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maccwall
Reg. May 2004

Posted 2006-11-15 12:14 PM (#51526 - in reply to #51515)
Subject: RE: 12 volt wiring - a primer for a beginner (idiot? ;))

Extreme Veteran

Posts: 524
500

Location: Lone Oak, Tx

NIce job on those LEDs 10Ha.Wood. You wouldn't happen to have a diagram on making those would you?

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10Ha.Wood
Reg. Jun 2006

Posted 2006-11-15 2:06 PM (#51530 - in reply to #51526)
Subject: RE: 12 volt wiring - a primer for a beginner (idiot? ;))

Member

Posts: 46

Location: Ottawa, ON

Originally written by maccwall on 2006-11-15 1:14 PM

NIce job on those LEDs 10Ha.Wood. You wouldn't happen to have a diagram on making those would you?

Thanks. They are dead simple - They are made up of three LEDs in series with a 150 ohm resistor all soldered onto some perf board. They won't work below 10 volts, and are slightly overloaded (too much current) at anything above 13.5 volts. They should be fine as long as they are not left on (for long periods) when the truck is running. (the alternator voltage is too high, but the current is still within the maximum rating)

The one that is lit in the pictures is made up of three groups of 3 LEDs (wire the groups in parallel) and draws 60 miliamps of current.

LEDs are not as efficient as fluorescent lights though. (yet) However, most of the time you do not need a lot of light and LEDs fit the bill.

Chris

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