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Where do I get good LEDs
By wdyasq, Section Light Posted on Wed Oct 25th, 2006 at 11:12:39 PM MST
Need several high-power bulbs

I need to put lights on a visor. Does anyone have good things to say about a product and dealer? The visor now has 2-3V (2 X 2 AAA batteries) incandecent bulbs. I prefer to use existing batterys and switches. I will be able to wire them to 6V is necessary. I do not plan on using the exiting mounts.
Thanks for your help,
Ron

Where do I get good LEDs | 8 comments (8 topical, 0 editorial)

Re: Where do I get good LEDs (3.00 / 0) (#1)
by JohnC (>>john_e_cox@yahoo.com<<) on Wed Oct 25th, 2006 at 05:26:53 PM MST
(User Info)

Just bought some, not long ago from www.au-long.com, in BC Canada.
I got 100 6000MCD 5MM LEDS Ultra Bright for $19.99 plus $2.99 shipping.
They all have the same intencity, so I would recommend these guys.

John E Cox
Ottawa, Canada

Re: Where do I get good LEDs (3.00 / 0) (#2)
by nothing to lose (nothingtolose175 at yahoo.com) on Wed Oct 25th, 2006 at 05:27:00 PM MST
(User Info)

Yes, I have alot of good things to say about Ghurd and his Leds.
I love the leds, he makes good stuff out of them.

If he has or wants to make the bulbs you need, they are worth getting. Maybe not the cheapest product out there, but far better quality than the cheap stuff for sure!!
.
nothing to lose

Spelin and tpying are my strong points, not electronics.

Re: Where do I get good LEDs (3.00 / 0) (#3)
by richhagen (richhagen (a t) Juno.com) on Wed Oct 25th, 2006 at 05:45:45 PM MST
(User Info)

Ron, I have obtained LED's from E-Bay with mixed results. I obtained some (approximately) 10mm white LED's from Ghurd that were fairly efficient when compared with most of the 5mm ones I had been getting. I don't have a way to measure the light output so that it can be compared with the power consumption, and I also don't know what angle or radiation pattern you are looking for, but given the application I'm guessing about 30 to 60 degree unless you are looking to focus farther out. The ones from Ghurd are probably about 60 degrees. I think he orders them in bulk from the manufacturer and then distributes them in smaller quanities through his company. Most of the Ebay vendors list the intensity of the light in microcandelas or MCD. Many are 15 or 20 degree LED's which would focus the light on a smaller area from the visor, but would measure a higher intensity in that small area. First I don't trust their measurements to be worth a hoot, and second, the intensity is a function of the distance and the radiation pattern for the light, so it wouldn't give you a good picture without other parameters for the efficiency of the LED. I'd rather see Lumens per Watt and then be given the radiation pattern. If you know approximately what size of area and how far away you wish to focus your light on then you can determine the angle of the LED. This angle is defined by manufacturers to be where the intensity falls to half of that in the center of the radiation pattern. If you need to adjust the area and focus, then you may want to look at a single wide angle LED such as LUMILEDS often used in flashlights in conjunction with an adjustable reflector, much the way many flashlights with conventional bulbs works. Rich
'A Joule saved is a Joule made'

Re: Where do I get good LEDs (3.00 / 0) (#4)
by dinges on Wed Oct 25th, 2006 at 06:05:47 PM MST
(User Info)

You'll probably have to rewire for 6V; leds have a Vf=3.4-3.5V, which means they need about 3.5V to give light (at least, a usable amount).

I suspect you're using 2 Lithium batteries (3V; CR123?), so you'd have to re-wire for 6V.

Most leds need about 10-15mA of current; but, when you want & get GOOD LEDs, the supplier should be able to provide a datasheet with technical information. However, settling for a current of 10-15mA, you can't go very far wrong.

Some drive them with 20 or even 30mA. Well, it's their cow... Some people drive their car at 200km/hr continuously. I don't.

Each LED needs its OWN resistor of about 6V-3.5V= 2.5V/.01A= 250ohm. Say, 220 ohm, which is a standard value. 220 ohm, 1/8W will be fine. You could put several LED/resistor units in parallel, to get the amount of light you'd need.

As far as to your question: my Dutch supplier won't be of much use to you.

My tip: do not buy batches on the web. I did. About 1/10 was either defect, or went defect very quickly. After a burn-in test, they seem to survive pretty well though. No more new failures.

Re: Where do I get good LEDs (3.00 / 0) (#5)
by Tom in NH (tom@altenergyweb.com) on Wed Oct 25th, 2006 at 09:46:28 PM MST
(User Info) http://altenergyweb.com

I've bought the Hong Kong variety LEDs on ebay with good success. I don't know how one would define "high quality", but the ones I ordered all looked ok; none were defective; they were all equal brightness, and all have stood up under the current I give them. I do stay within the manufacturer's ratings.

I have managed to blow LEDs, but in every case, it was because I exceeded the manufacturer's forward current rating. If you exceed it just a little, you shorten the life of the LED. It won't blow immediately. If you exceed it a lot, it will blow immediately. Sometimes it can be quite spectacular. This applies whether or not you give each LED its own resistor. -tom

Re: Where do I get good LEDs (3.00 / 0) (#6)
by ghurd on Thu Oct 26th, 2006 at 05:45:57 AM MST
(User Info)

Hi Ron,

Tell us more about this visor. The yellow HF $4.99 on sale for $0.99?

What will it be used for? Spot light or area light?

White LEDs?

Check your posted email.
G-

Re: Where do I get good LEDs (3.00 / 0) (#7)
by ZooT on Fri Oct 27th, 2006 at 12:34:10 AM MST
(User Info)

I've been playing with some so-called UFO LED's, and don't know yet how long they'll last, but they are very bright and have a wide angle field to boot.
They're rated at 3.5-4v forward voltage @ 50ma, but I'm running them at 3.5v 30ma.

Here's what they look like:

Re: Where do I get good LEDs (3.00 / 0) (#8)
by RumiUK (sunpowerathotmaildotco.uk) on Fri Oct 27th, 2006 at 09:55:49 AM MST
(User Info) http://www.sustainable-systems.co.uk

Hi I run a small RE company and Luxeon LEDs is one of the products we do. Send me your requirements I will see what I can offer you. Rumi

Where do I get good LEDs | 8 comments (8 topical, 0 editorial)

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