Original DIY LED Page
This is where it all started in 2005, looking for a better idea.
LEDs are far and away the best solution for lighting in any recreational vehicle. Just as fluorescent lights were a major advance on incandescentlighting, LEDs are now a major advance on fluorescent. You can havearea lighting and spot lights and reading lamps in any ambience you prefer. You can do all of this at low cost and use tiny amounts of
energy from your batteries.
If you are sceptical, read on. Others were as well until they saw them in action.
You will still read statements at odds with the above today, especially claims that LEDs are little more efficient than incandescent lights. You need the full story.
Since my article in the February 2007 issue of the Wanderer, I have had some requests for a simple DO IT YOURSELF set of instructions for beginners. This page has extensive information and you need to scroll down to find it all. It is a bit of a jumble as the page has evolved over the last year and a half. Beginners might like to build a simple lamp with about six LEDs for a start. The best guide here will be the pics of the early lamp like the one shown in my air con housing. I used four LEDs but, if you use six, put them in two series strings for 12 volts or one series string for 24 volts. All you need is the six LEDs a resistor or two, a piece of masonite or similar and some solder. After you build the first one you can join the ranks of expert LED innovators. All the detail is below, including where to get your LEDs.
Now for the pictures:
First is the ceiling fixtures:
I made six strings of six LEDs in series, each with a 270 ohms resistance for my 24 volts. This is an early picture above with 18 LEDs and I later settled on 36 LEDs at three watts for suitable area lamps. More were easily added.
For 12 volts you will need twelve strings of three LEDs, each with about 150 ohms of resistance for each series string.
I mounted the LEDs on a strip of masonite and made it slightly longer than the space between the empty globe sockets, for easy mounting. This made it bow slightly and spread the beams from the LEDs effectively.
This assembly has about $20 worth of parts for 36LEDs. It rates about 3 watts compared to the 24 watts incandescent it replaces.
Some observers say there is more light from the LED assembly than from the 24 watt light behind. Maybe there is below where you want the light, but at the level of the curtain tops and on the ceiling it gets dim compared to the incandescent. You can detect this in the comparison photo. Later light measuring confirms that the three watt LED lamp performs about as well as a 60 watt incandescent over the area from wall to wall.
You will wish to diffuse the output from the LEDs. Have a look at LaWrie's website and how he has sanded the LED tops. I found the clear crystal diffuser in the pic above had a good effect. I am pleased enough to convert the other two incandescent ceiling lamps to LEDs.
The other pics show construction detail for spotlight and reading lights using my surplus air conditioning vents. Four LEDs fit nicely in each. Four in series for 24 volts, I used 720 ohms (The table shows 560 ohms but brightness is still good at 720 ohms). Four is too many for 12 volts. Two or three in series would be OK Parts for the double spotlight reading light run about $4 and rates about 0.8 watts for the 8 LEDs used this way. The board is masonite cut with a cheap Bunning’s hole saw set.
As I made more of these I used six LEDs in place of four. It is best to use the maximum number in series for a particular voltage to increase efficiency.
Wiring and soldering on the back of the board, you will see, is quite simple. A little practice with a temperature controlled soldering station and you will be an expert. A small regular soldering iron with a fine tip will do in a pinch, but use caution as the temperature of these are all over the place. Use rosin core solder for electronic work. Wipe the tip of the iron often, on a damp sponge or cloth. Melt solder on the tip so it looks shiny and wet. This is called tinning. Put the tip to the join for a few seconds and then bring and allow the solder to melt. Joins should look bright and shiny.
These spotlight-reading lights can be swivelled to point in any direction where brightness is wanted. There is virtually no heat to burn your fingers, waste energy or heat up your interior.
You can determine polarity of the LEDs in three ways. The negative side is the flat spot or the shorter lead. By looking at the electrodes through the plastic, you will see they are different. I find this third way easiest when putting the LEDs on a masonite board. Drill two holes just large enough to fit the LED leads. Put a dab of glue on the LED base, keep wire leads clean, push the LED in place and bend over the leads. The wire leads are delicate and are now reasonably protected. Solder as shown in the circle picture and trim the excess leads. Now that I am down to an assembly line for these spot lights I have decided to mount the resistors in the same way as the LEDs, through the board. This keeps the whole assembly tight and neat. You can cover the exposed wiring with a suitable insulating material. I used masking tape and painted around the edges with contact cement. You could also use hot melt glue.
FEB 06 The LEDs are now reported to be 125000mcd. You can request colour to be with a yellowish tinge or with a blueish tinge. I like the warm colour of the ones with a yellowish tinge. Write to Jacky from the eBay site below.
I got my LEDs from this eBay site:
http://stores.ebay.com.au/HKJE-Led-Lamp-Center_W0QQssPageNameZviQ3asibQ3astoreviewQQtZkm
I mounted them on a one of the circuit boards another member had made and cut off the extra piece.
The tiny spots you see are the LEDs and they produce considerable light. There are are 15 on this board piece. Their wide beam covers the whole bed and up the bus walls with even illumination.
I am considering making the next area light using a mix of the colours of the 10mm 125000mcd ones and some of these as well.
Comparing this as a lamp with one containing 12 of the 10mm LEDs:
Spread is wider
Light is cooler
Brightness a little less but still easy to read fine print.
I like them!
12 VOLT SETUP- Will fit 27 LEDs or adapt to 36 LEDs
ADAPTED FOR 24 VOLTS
18 BLUISH 9 YELLOWISH 9 WARM GOLDEN PRODUCES OVERALL WARM WHITE
I must get around to doing a cleanup on this page. Below is most of the text from my article for the Tech Notes. It is the most current if you find slight differences in the statements which follow.
THE NEW LEDS FOR MOTORHOME LIGHTING
Light emitting diodes are constantly evolving and have reached the stage, in mid 2006, where they are suitable for the full lighting needs in your motorhome. This has not always been so, and they have had more limited special applications in the past.
They are so good, that with current LED technology, you can expect to consume only a few amp hours from your batteries each day. Even if you forget to turn your lights off, the consequence will be minimal. I run mine from my starting batteries without concern about cranking the engine a couple of days later.
The better option at the moment is to do it yourself, as the finished bulb replacement types might contain LEDs less advanced than the singles you can purchase. With the finished offerings light colour is not always acceptable and the fittings can sometimes protrude and annoy with unwanted glare. Making your own will save money and produce custom lights and enclosures to suit your needs. There is the added advantage if you are set up for 24 volts as the available bulb replacement types are all 12 volt.
LaWrie Beales and I started experimenting independently on our motorhome lighting last year. We have come to the same conclusion when the job was done. LaWrie’s bus is 12 volts and mine 24 volts, but the lighting effect and energy savings are the same. A typical, medium sized motorhome might use about 150 LEDs to provide total lighting. At a price of 50 cents each or less, it is certainly economical. Arranged for the least energy use this will total about 12 watts. You will likely be consuming half or less of this most of the time. Two overhead area lamps of three watts each will illuminate your interior. These will each contain about 36 LEDs. Spot and reading lamps of one or two watts will make up the rest.
These LEDs are cool to the touch and will likely last so long as to never need replacement. You can mix a choice of white colours to match the colour warmth of other lighting. If you can do simple wiring, learn to use a soldering iron and follow easy directions, DIY is the way to go. If not, try out the ready made ones in a couple of your light fittings. Different types are available. One kind produces considerable light from a single high intensity LED, but also produces quite a bit of heat to eliminate. This consumes extra energy and you are likely interested in this exercise for the promise of the tiny amount of energy needed to provide lighting in you motorhome. LaWrie tried a pair of these hot ones from Hong Kong at $18 each and reports that they make excellent reading lamps even if not as energy efficient overall. Here the Luxeon type LEDs are lensed and controlled for best reading light output and current draw.
LaWrie and I have been touting the virtue of LED lighting for most of the past year. We have encountered our share of sceptics and those who claim that fluorescent lights are a better alternative at present for cost, light colour, light output and efficiency. LEDs beat them hands down on all counts. Those who have seen our finished efforts are all convinced and light measurements with a lux meter confirm the comparison observations. There are some members now redoing all of their motorhome lighting with LEDs with considerable enthusiasm. Light measurements support the claim that 3 watts of LED lighting will perform better than a 60 watt incandescent globe or a 12 watt fluorescent fixture. They can do this and produce the colour and ambience you desire and probably last a lifetime as well.
Arguments against the suitability of LEDs for general lighting have revolved around the major fact that the best LEDs today are only slightly more efficient overall than the best fluorescents. This is only part of the story and others have been disappointed by unattractive LED light colour and narrow beam angles for the light output. Conventional light sources radiate light in all directions. The inside of a large ball would be illuminated equally over its entire surface with such lights at the ball centre. LEDs radiate a cone of light which can vary in width from a few degrees to 140 or more. It is this ability of LEDs, to provide light only from wall to wall where it is desired, which provides a large part of the efficiency advantage. If we only wish to illuminate the lower third of the inside of our large ball, we already have an energy savings of about two thirds. Mixing LED shades of white and diffusing narrow cones solve the other objections.
There are also offerings newer than the familiar plastic LED shapes in 3mm, 5mm and 10mm diameters. Surface
Replacement with LEDs is also a simple fix where existing lighting cables have excess voltage drop. I used the existing bus light wiring which is more than adequate and added circuits with cheap speaker wire.
So, if your average power consumption for lighting in the evening is around about six watts, with half of the LEDs on, and you use them for six hours, you have used a mere 3 amp-hours from your 12 volt batteries. You are well on your way to creating an energy efficient motorhome.
Thanks are due to LaWrie Beales, Laurie Hoffman, Ian Bond and Ian Lock and others for their enthusiastic support and help.
This page has evolved from experiment over several months.
12 LEDs make a good sized spotlight at one watt.
Twice this form an excellent reading lamp at two watts.
Total lighting for a medium sized motorhome should come in
at about 12 watts with roughly 150 of the good LEDs.
To get these results and desirable light colour, read on!
Above are just some applications of LED lighting. It shows the general setup methods which you can adapt to fit any housing you may choose to use.
You can also use light gauge wire at these miniscule currents. I wired all mine with speaker wire from the local discount store. It has a brown and silver wire to keep the polarity correct.
The pics at the top of the page show the results of the LEDs in construction and use.
These are the large 10mm, 110 000 mcd superbright whites. Now 125000 mcd. then later 140000mcd.
This gets confusing. Take the following two examples.
New Product 10mm JUMBO White LED Lamp @140,000mcd ----- 13 degrees
New 5MM Brightest White LED Lamp 50,000mcd ------ 25 degrees
The above two examples would suggest that the 5mm produces more light than the 10mm. If you double the viewing angle your light shines on an area four times as large. So if reduced to half angle the 5mm should be 200,000mcd. This is where the hype seems to come in, and the specs need viewing with some doubts. Essentially, I think up to date LEDs will likely produce similar amounts of light. 5mm, 10mm or even the tiny surface mounts, all in same ballpark. Luxeon types are different though, high light output, expensive, run hot and more difficult to use and save energy.
Cheers,
Barry
Also check out these sites for additional info on LED light output and circuit arrangements and resistor choices.
It is difficult to make light output comparisons with LEDs measured in mcd at the source and other lights measured in lumens at the surface on which they shine.
I will try the following bold statement in rough rounded numbers. (current technology for similar light output where you want the light to shine.)
FLUOROS USE ABOUT ONE FIFTH THE ENERGY OF INCANDESCENTS
LEDs USE ABOUT ONE FIFTH THE ENERGY OF FLUOROS (Different reason for this)
THUS LEDs USE ABOUT
I do get some flack for the above comparison. I am reluctant to remove it just yet and it does seem at odds with the latest theory only having the best LEDs equal to fluoros for comparison of efficiency.
I am not stating that LEDs are five times more efficient than fluoros. I am saying that, if you replace a fluoro with LEDs to illuminate the area where you want light, you might use about one fifth of the energy. Fluoros radiate in 360 degrees. There seems little point in diffusing your LED area lamp beyond about 160 degrees. Not unless you are keen to illuminate the ceiling.
For the latest and some theory have a look at this link.
http://members.misty.com/don/ledx.html
Don Klipstein's LED Main Page
Consider this:
Replace a fluoro area lamp in the ceiling of your RV with a LED lamp as described.
Now:
If it walks like a duck
If it quacks like a duck
But gets by on much less duck food.
You get the idea.
The only way you will know how good these LEDs are will be when you see them working.
Detractors will argue for Fluoros until they see them as well.
Their Fluoro will be running at 12 watts or more.
The LED replacement will be about 3 watts.
These links are useful as well.
http://led.linear1.org/led.wiz
http://www.superbrightleds.com/led_info.htm
http://www.lpelectric.ro/en/support/lumeni_en.html
The site below from Dan Fink has some good ideas and diagrams. LEDs have since dropped much in price and increased much in performance since it was written, especially the white ones. THIS IS A VERY USEFUL WEBSITE. Links will help you design a LED flashlight and other useful tips. You should read the comments about LED efficiency with regard to the age of the site.
I have copied these circuit digrams from the website for convenience. Notice how the strings are connected in the second diagram. You can have as many strings as you want. Just put 6 LEDS in place of the three if you run on 24 volts.
Also USE THE RESISTOR VALUES IN MY TABLE. THEY WILL PROTECT YOUR LEDS BETTER AND GIVE AMPLE LIGHT.
http://www.otherpower.com/otherpower_lighting_leds.html
Dan has written to me re this link and tells me he is currently updating it.
It is not the best idea to use fewer than three LEDs in series for 12 volts and six for 24 volts. When you do, energy is wasted by dissipation across the resistors. This gets quite serious for one or two LEDs alone at 24 volts.
The WARM WHITE LEDs arrived from Jacky today.
These are the 10mm ones rated at 70000mcd compared to the whites with the bluish tinge at 125000mcd.
Now for the test results:
These warm whites are labelled as GOLDEN WHITE on the packet.
The initial impression on lighting them up is that they are amber. They glow this colour when you look at them.
Used alone they might shed a light which is a bit too much amber in colour.
I mixed some with the bluish whites in one fixture and with other yellowish white ones in another.
I would judge the overall effect as quite similar to the warm white light from a warm fluoro depending on the mix.
If you try a light fixture with a mix of one third bluish white, one third yellowish white and one third of these new amber warm whites, the overall effect is quite pleasing.
A good diffusing cover (clear crystal type) will mix the colours together for an overall even effect.
LaWrie might try the mix with his top sanding method of diffusion.
Some are on their way to him as well.
I just put together a reading lamp for another member. It has 12 of the really bright LEDs so total output is about 1 280 000 mcd on the specs. It is set up for 12 volts and in total rates about one watt. I mixed some of the various white colours for a warmer look. I also sanded the tops flat to try without the need of a diffusing cover.
I have now run out of LEDs and think the job is finished.
LED Summary for my bus:
150 LEDs in 11 lamp fittings producing a warm light colour.
Total of approx. 2200 lumens (roughly equivalent to three 60 watt household light bulbs, but more effective because they do not need to illuminate the ceiling.) Interesting because that is three North American 60 watt incandescents. It is about four Aussie ones. I used to tell Canadians that Australians did not need to change light bulbs nearly as often. Now I know why!
Total cost including resistors and solder a little under $70.
Another $8 if you count the switches and some wiring from Oatley Electronics.
Now, if there was ever a need to have all on at once:
Total current draw 0.5 amps at 24 volts or 12 watts.
Most of the time, for lounging, reading and computer use, there is 24 LEDs lit for 2 watts total.
Just as, not all motorhomes perform equally well, same goes for LEDs.
I have not seen these really bright ones in commercially completed fixtures yet, but it is bound to come.
And, if the LED gets hot, that energy to produce heat is not making light.
My little LED tester arrived today from
Measuring angles and comparing with stated intensity in mcd seems to indicate that the specs given with some LEDs should be largely ignored as hype.
They are still great performers and other writers have confirmed what Lawrie and I have been claiming, 3 watts of LEDs can be expected to serve as well in your motorhome as about 60 watts of incandescent light and 12 watts of the best fluoros.
The 10mm bluish and yellowish (125000mcd to 140000mcd) produce an intense bright spot about 3 inches in diameter at 24 inches. The golden warm ones (70000mcd) the spot is about 14 inches at 24 inches. You can figure the beam angle if you have a calculator with tan function from the above. I don’t have one handy. Dimmer illumination is produced over a much wider area, but this is probably from diffusion within the LED plastic. The yellowish had a second moderate intesity ring about 8 inches wide outside the 3 inch intense bright spot. This seems at odds with LaWrie's observation so there may be batch variations. None of this matters much. Diffuse your LEDs well for an area lamp and you will be delighted with them.
Below are some pics of a monster built by Cuppa with 75 LEDs. This one should come in at about 6 watts and draw about half an amp at 12 volts.
A handy piece of board is drilled to accept the LEDs and the leads bent over, soldered and then clipped neatly. The work is now ready for the addition of 25 resistors. (150 ohms for 12 volts in this plan). Resistors could be placed on the LED side through more holes or neatly added to this side below
JUST A CAUTION! The thick wire shown as "rails" on the wiring pictue below could act as heat sinks and make soldering more difficult. Simplest alternative would be just to bend the LED and resistor leads in line to make the rails.
Again there is a mix of three colours of LEDs to produce a warm white light
Here is the monster fired up and glowing bright.
The picture below shows a pair of Luxeon type LEDs mounted in one of my air con ducts. These are intensely bright and light up an area well enough to show the bright area even in daylight. They are wide beam and need to be heatsinked. This series pair is drawing 550mA at the moment arranged in series. That should be about 7 watts at about 12.8 volts. I designed for 13.8 volts to allow for charging.That would make them even brighter.
It would be interesting to compare this lamp with Cuppa's monster above for light output. These need to be recessed to discourage looking directly at the LEDs. Might not be good for the eyes, they are so bright.
Lots of light in an acceptable cool white spread over a wide area.
I think Cuppa's shearing monster may have it beat for light output and current draw. I would choose the 10mm LEDs or the tiny surface
Have a look at this website for printed circuit boards. There are some interesting possibilities and excellent pictures and ideas. I will report later after trying some.
http://stores.ebay.com.au/MeasureExplorer
SOLDERING SURFACE
You will need a printed circuit board of some kind, like Vero Board or those made for the purpose and available on eBay (see above site). You will need the solder tabs to be spaced correctly to accept the surface
First “tin” a little solder on one of the printed circuit board tabs. Now you need to hold the surface
don't overdo it.
Takes a little practice but keep the soldering iron off the LED and allow the melted solder to flow to it.
If you want to get fancy you can use surface mount resistors as well. There is a photo above with 15 of the larger surface
bravenet.com