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Light Emitting Diode Lighting
11/9/03

After I bought my 1999 Dodge Ram Cummins, I bought a used topper for it. After camping in it, I decided I needed a few improvements to make it more comfortable. I slept on an air mattress the first night I camped in it . While it was comfortable, it was very cold. The metal of the bed conducted all of
my body heat away and I was miserable. So I built a wooden platform to get my bed off the cold metal. This also gave me plenty of storage space underneath the platform for all the camping gear. While this was quite a bit warmer, two separate air mattresses went flat in the middle of the night, leaving Jean and I to wake up stiff and sore on the hard wood deck. The next step was a foam mattress that solved that problem. Jean got the foam at  The Foam Source  in Boulder. They  cut the foam to size  and Jean sewed covers for them. We had to wait a couple of weeks for the foam to be delivered to their shop but it was worth it to get the right size.


Truck Bed

Now we had a nice place to sleep but it was a bit dark at night. I needed to install some lights The truck had a trailer plug in the bed for a gooseneck trailer so power wasn't a problem. However, I didn't want to run a big load off the plug since it was fed from the start batteries. It has  two start batteries and would be pretty hard to jump it if we ran them dead. Since I like to get off the beaten path, I didn't want to risk running the start batteries down in the middle of nowhere just to light the topper.

I do  lighting design at work so I had a pretty good idea of what kind of light I wanted. Incandescent lights convert 90% of the current they draw into heat with only 10% of the current producing light. Good fluorescent light are about 25% efficient but 12v fluorescent lights have terrible color rendition. They produce light that is mostly blue and even though there might be a lot of light, it is still difficult for the eye to see detail with poor color rendition. There have been some advances in white LED lights in the last couple of years so I started to look for an RV LED light.The latest, high tech LEDs have an efficiency approaching 85% with a good color spectrum so that people don't look like zombies. And finally, a good incandescant lamp is good for about 2000 hours, a fluorescent about 20,000 and an LED is good for 100,000 hours. I sure like the idea of a lamp that lasts longer than I'll own the truck. I made some sacrifices in lamp life for output, but I'll describe that later.
So I started to look for LED lights for RVs.

Since LEDs offer so many advantages I was sure that there would be a ton of LED lights for sale on the net. I was surprised to find that there isn't a whole lot available. The LED Light.com was the only site I found  that has LED lights that I liked. Unfortunately, like any new product, the prices are a bit higher than I wanted to pay.
  I started to look for DIY LED lighting sites.After a lot of searching I found a great site for the construction of LED lighting strings at the Home Built LED Lighting site.  So now I've found a design for the LED lighting but I needed an LED source. At a boat building site I found  White Light LED that has good prices with white LEDs being $1.00 each. The rest of the parts I needed I got from Radio Shack.

At the
Home Built LED Lighting site you can learn about what level you want to drive the LEDs. I designed my circuit to run at about twice the level of current that will give maximum lamp life. I'm sacrificing lamp life for light output and its not much of a sacrifice in my mind. Since I'm overdriving them by about 50% I've knocked lamp life down to 50,000 hours. I've found that the deep cell battery I installed to power the truck appliances runs at a little over 13 volts when fully charged so I'm overdriving them more than the 12 volts I designed around. So lets say I'm down to 25,000 hours. That's 5 years worth of everyday use.

 
I spent about $25 per light fixture on parts by the time I was done. The total power requirements for all the lights is 7.2 watts. I generally only have one string on at a time, which is 2.4 watts. That's only 0.2 amps so If I run them all night I've put a 2 amp-hour load on my battery.

Okay, I've talked a  lot about LED lights so what's the end result? Here's  what my lights look like.

Truck Side

This is my truck at night with all the LED lights on. Reading lights, bed lighting and tailgate lighting.

Truck Side 2

The tailgate lighting is so we can cook at night. If I close the tailgate, there's enough light to read by if you set a chair close to the bumper. I'm thinking about putting a light on the hatch so I can light a wider area. The lid of the stove casts some shadows on the burners with this arrangement.

Inside Topper
 
This is what it looks like inside the topper. There's plenty of light inside. The light in front has two sides. I can turn on the light on my side to read and Jean can turn the light on her side as well. The light is directed well enough that the person on the opposite side of the light can sleep while it's on.

 With incadenscent and fluorescent lights, you need some kind of fixture with reflective surfaces to direct the light where its needed. LEDs are manufactered with with set angles of dispersion. This means that you can stick an LED over an area  and aim the light where you want.
 Area Light

The six  horizontal LEDs are a mixture of 20 degree and 120 degree beam widths. The 20 degree LEDs are pointed towards the front of the truck and the 120 degree LEDs are pointing  towards the back of the truck. This lights the whole bed more evenly then using all 20 degree lights as I had originally  designed it. The six vertical LEDs are for the tailgate. Since the light is fairly high off the tailgate, the 20 degree LEDs have enough distance to spread out for even light. 
 

  Reading Light
 

These are all 20 degree LEDs with 3 on a switch.The light comes from over your shoulder so there isn't any glare while reading.

New!! Updated LED Light Project!!

Here's some links to white LED stuff for those who are interested.

LED Reading Light

Learn About LED's

The Perfect Light

White LEDs from a Wide 1.6V to 5.5V Input


Home Built LED Lighting

White Light LED

LED Lighting Suppliers

Tons of LED Links


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