|Light Emitting Diode
After I bought my 1999 Dodge
Ram Cummins, I bought a used topper
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
underneath the platform for all the camping gear. While this was quite
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
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
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
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
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
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
At the Home Built LED
Lighting site you can
learn about what level you want to drive the LEDs. I designed my
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.
my truck at night with all the LED lights on. Reading lights, bed
lighting and tailgate lighting.
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
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.
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
stick an LED over an area and aim the light where you want.
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
is fairly high off the tailgate, the 20 degree LEDs have enough
distance to spread out for even light.
all 20 degree LEDs with 3 on a switch.The light comes from over your
shoulder so there isn't any glare while reading.
LED Light Project!!
Here's some links to white LED stuff for those who are interested.
Learn About LED's
LEDs from a Wide 1.6V to 5.5V Input
Built LED Lighting
White Light LED