| Author |
Message |
Stephen Fessenden (Sffess) (65.130.16.183)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, November 29, 2002 - 11:18 pm: | |
I just installed LED night lights in my ceiling lighted vents. Made them myself with ultra bright yellow LEDs. You could use the bathroom at night with only these. You could read by them in the living room, or get water at the kitchen sink by them. For a pure night light use 5 LEDs is actually too bright. With 100,000 hour life and very low current draw. I will probably turn them on at the beginning of a trip and turn them off when we get home. (These replace old ineffient blue lights, bulbs with a blue plastic cover over them to subdue the light.)
Used two sets of 5 LEDs per vent/fan light. Since they are behilnd a plastic diffuser, I did not need to worry about making them extra pretty. I used pieces of perf board about 1/2 inch wide by 2 inches long and put 5 LEDs in series in a zig zag line (to save space). Terminated in an 800 Ohm resistor, (actually used two 1600 Ohm resistors in parallel). Connections were carefully made mechanically then soldered. The perf board was fastened to a small angle bracket made from a scrap of thin aluminum with a small screw, nut and toothed washers, making the ground contact for the LEDs. Resistor could be at either positive or ground end of circuit. The perf board could probably be bent with a heat gun before assembly and no separate bracket would then be needed. I insulated the open connections on the back of the perf board. Could use tape, or liquid tape.
Up to 12 LEDs could be used in series for 24 volts and the ballast resistor becomes 100 Ohms. Since I did not have specs for these LEDs the calculations were done estimating a 2 volt voltage drop per LED and current of .020 Amps in the entire circuit. |
Stephen Fessenden (Sffess) (65.133.74.25)
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Votes: 0 (Vote!) | | Posted on Saturday, November 30, 2002 - 7:14 pm: | |
Same light on 12 or 24 volts, almost, even though they had a ballast resistor calcualted for 28 volts. Proof that you could use an LED lighting system as a dual voltage tail light system on a trailer or toad. Providing you figure out how to protect the cars wiring from 24 volts getting to things. In any case, a separate LED lighting system could be glued to the inside of the tail light lens, out of the way of the bulbs and your toad could be hooked up to a 12 or 24 volt towing vehicle with no changes. If you use LED lights with a ballast resistor for 12 volts on 24 volts they will work for a fairly long time but not the expected 100,000 hours. |
CoryDaneRTSIIIL (4.17.253.42)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 30, 2002 - 9:02 pm: | |
Stephen
This is not exactly the proof you think you have.
The LEDs will work for SOME light effect but you cant just attach them anywhere under the STOP lens of a car or tow vehicle.
- Though TRUE, the leds give off light at the requried voltage but the reflectable portion of the red stop light lense requires the light source be in a specific location, other wise, you will see it light but it loses the distance of visability real fast, falling under the requirement by law.
- This was a problem when I converted my RTSII STOP/SIGNAL/TURN lights over to LED lighting. The solution was to use a pre-made led fixture that "FLOODED" the lens with light to keep in the legal standard. I hazard to say, a few led's will not flood the lens with enough light to keep from catching the eye of the long arm of the law people.
- If you look at some of the LED lights specifically made for STOP/TAIL/TURN signals, they are made with specific lenses and specific reflectability for the purpose of enhansing the actual LED lens as it points light out from its source. OTHER than clearance lights which have from one to three leds in them, the smallest number of LED lamps in a stop fixture was about 12 but they incorporated some slick reflector surfaces to make each LED look much larger. All the others had, in a space 3" diameter, full of LEDs, side by side filling all voids.
- The best LED Stop/Tail/Turn technology was on the Cadillac Devil but its lens is intense with shapes to make the lens look full of light from the led source. Until a manufacturer makes a lens similar for buses, the only answer seems to be to flood the lens with SUFFICIENT LED light source to be seen on the brightest of sunny days and stay in the legal guidelines.
- I dont think a couple of leds will suffice in any event for stop lights, but for inside the coach, as night lights behind a light diffuser, I think they are great and, as a matter of fact, will be making some myself. Great Idea Guys!!! - cd |
Jerry (152.163.188.227)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, December 01, 2002 - 10:20 am: | |
West Marine chain stores and I'd guess others sells a about 5-7 LED light fixture for about $20-25. Fits is a 1-1/2" hole about 1" deep. Sealed unit runs directly on 12Vdc -- great for a shower light. |
Stephen Fessenden (Sffess) (65.133.74.98)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, December 01, 2002 - 11:36 pm: | |
I have been making my own with Ultra bright yellow LEDs I bought on Ebay for 38 cents each. comes to about $4 a fixture. Ebay seems to be a good source for Ultra Bright LEDs if you keep checking until you find a good price. |
Stephen Fessenden (Sffess) (65.133.74.98)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, December 01, 2002 - 11:41 pm: | |
Cory, I don't just have some light on half voltage. I have almost the same light. Maybe 75% of full power light output and still at the same wavelength, unlike underpowered incandescent bulbs. |
CoryDaneRTSIIIL (4.17.253.220)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, December 02, 2002 - 12:53 am: | |
Cant you put say 8 leds in a row,(series) eliminating the resistor???? Like you would with low voltage incandescant bulbs |
Craig S (65.202.123.254)
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Votes: 0 (Vote!) | | Posted on Monday, December 02, 2002 - 8:23 am: | |
Cory,
You can't install the LEDS without a resistor. It's what sets the current through the circuit. After subtracting the LED drops, you use ohm's law to calc the resistance(R = V/I) of the left over voltage, then you calc the wattage(P = I*V). I read on another thread that you need at least 4 volts of non-LED voltage the get a resistor within a reasonable value and size. The nominal current for an LED is about 20 milliamps. This is the key factor.
Craig S |
Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, December 02, 2002 - 3:07 pm: | |
I guess my last post of this got lost somewhere..
here's some explanation of how it all hooks up...
http://www.heartmagic.com/00LEDtalk.jpg
Cheers
Gary |
Will MC-7 (12.162.39.178)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, December 07, 2002 - 9:52 pm: | |
You can also skip the physics and go to Auto Zone and purchase an 1157, 1156 (tail light) LED bulbs that fit right into the original sockets and be done with it.
They also have side marker and other L.E.D.s that replace bulbs.
The future is here!
Will |