12V DC lighting...HELP!

[ChainsawGrandpa]

People keep saying I can do anything. Well, I know there is one
thing I can't do well, and that is anything electrical. The best have
tried to teach me. Just doesn't take hold. Here's my situation.
I am building a storage shed. There is space for the car or truck
to pull up right next to the building. I want to put jumper cables
on the 12V battery, and clamp the other end to terminals in a box
on the building. This would provide temporary lighting for when we
need to get in the storage shed. I know I just can't get some bell
wire and attach an LED to the wire every 5'. Any idea of what I will
need to do? Do I need a resistor(s)? I have no idea of where to start.

Thanks in advance.
-Rick

[gregorama]

You can just run wiring like you would the house; run romex between fixtures. Polarity isn't important if you're only using incandescant lights. Mount a couple bolts, tied to the Romex WITH A FUSE inline (before) the switch, inside a junction box. Best to connect the battery, then turn on the switch, so's you don't spark and blow yourseff up... :twisted: Hang up some RV lighting http://www.campingworld.com/browse/products/index.cfm?deptID=4&subOf=52,23&prodID=1578. The LED idea has much merit; the problem as I see it, LEDs are great for directional or task lighting, but not for overall lighting, and they can be expensive. You can get 12 volt halogen fixtures, but they can put out significant heat, watch what you mount them to. If you like, put in a car battery, tie on a small solar panel (polarity does matter here!) the kind you'd throw on your dashboard to trickle charge the battery, and unless you're in the shed for an extended period, the hot Wenatchee sun should be plenty juice. LEDs would be great in that use, since they draw so little. Remember, watts (bulb total)/volts (12) = Amps for your fuse (assuming you're not going crazy on bulbs and other loads) . Bigger wire is always better and brighter - 14 for a few bulbs, 12 if you're going for more. If you're going for the blinding effect, you need to be more careful about overloading things.. You can get 12V bulbs with regular house-type bases, and mount regular porcelin fixtures. You should stay under about 60-80 watts...

Does that help? If you have more specific questions, feel free to ask.. :wink: Check West Marine ,too..

Greg

[ChainsawGrandpa]

Thanks Greg!

That makes it a little clearer. Was thinking of the small 3.5 - 4.5V
single white light units. Put a string of 14 on each side of the shed
for a total of 28 LEDs. The smaller shed would use a single wire of
14 LEDs. Seems like a lot of battery (500 - 750CCA) for such a small
draw. Should last at least 20 minutes. :wink:

How about a small recepticle box with two 120V plugs in it? Then
use 14/2 wiring with a junction box at each LED? Maybe just wire
in series. The jumper cables could have the large allegator clips
for the battery, and a 120V type plug on the other end. Of course,
that would leave potential for the 12V being exposed at one end of
the cord. Put the fuse (10W?) in the recepticle box. Sound good to
you? Thinking 28 LEDs in the large shed should be plenty. We don't
need to see well, just enough to get a shovel or rake, and not trip on
something.
-Rick

[gregorama]

As a wise man once said, "Sure, you can do it that way, but why?" :wink: You're talking about individually wiring 28 boxes with Romex, with one LED in each one? That sounds like a lot of expense and work and a high possibility of loose connections (AKA sparks). The basic RV ceiling light is brain-dead simple. For the cool love-shack factor, you'd be better off with an LED rope light, may be available at Christmas at the RV/marine places. I first wrote using a permanently mounted set of cables, but a couple posts would allow you to keep the cables in the truck for actually jumping something, so I revised it. If you're going to cut the cable to put on a plug, you might as well make it permanent and secure.

Remember not to get your V's and A's and W's confused. Viewed from a plumbing perspective, Volts is a measure of pressure, and Amps is a measure of volume. Watts are the product of the two, Volts x Amps, conversely, Amps is Watts/Volts. So if you have a 20 watt halogen fixture, at 12 volts, you're drawing 1.7 Amps; and at 120 volts, you're drawing .17 amps. The length of a DC circuit is important (count both ways because electricity flow out one wire and back on another). The fuse is there to protect the wiring; if you try to push too much water through a pipe, it will stretch (heat up in electrical terms).

Here's a good way to figure it right:
http://www.boatus.com/boattech/CircuitProtect.htm

There's some kind of wordy help at: http://www.ibiblio.org/ecolandtech/alternative-energy/homepower-magazine/archives/14/14pg32.txt

BTW, for a quick and dirty reference/textbook , try www.allaboutcircuits.com

re: the battery, those little solar panels you can get for $10 are just a trickle charge, so you need to have a reasonable capacity to store all those trickles. Anyway, a smaller rechargable battery would cost almost as much. If you're just grabbing a shovel, (in the dark? makes me wonder!?!?:shock: ) a motorcycle battery would work fine.

When it comes to electricity, sometime the KISS method is the safest.. 8)


Greg

[wood bug]

I would buy a solar charged security light and get my 500 watts of light think Lowes has them for about 60 bucks

[gregorama]

Problem solved...

http://www.northerntool.com/webapp/wcs/stores/servlet/NTESearch?storeId=6970&N=0&Ntk=All&Ntt=solar%20shed&Nty=1&D=solar%20shed&Ntx=mode+matchallpartial&Dx=mode+matchallpartial