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Old 03-10-2008, 11:34   #31
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A reply to Bill's and others comments. I am in the Marine LED business, so I think I can comment. Yes, you absolutely get what you pay for, as long as you understand what it is you need to be looking for in LEDs. Some folks sell cheap LEDs to unsuspecting boaters at high prices! Everything Bill says is correct. However, recent advances in thermally-efficient substrates and SMD LEDs have allowed very high outputs without the bulky heat sinks. At least to the extent that you can get the same output as a 10W halogen without exceeding design parameters of the LED. The newest high-output LEDs create less than half the heat at the junction compared to those of just a few years ago.

Here are a few rules for marine LEDs. I have a white paper (LED for dummies) that I can send to anyone that is interested.

1. Ballast resistor controlled LEDs have NO place on a boat (for very many reasons, least of which is they are not as bright, and won't last the summer)

2. At least 90% of the LEDs sold to boaters are ballast resistor type (which is why many major marine retailers don't carry LEDs anymore)

3. The best LED luminaires are bin selected for color temperature and forward voltage (and UV output) Bin selected LEDs are way more expensive than orphan LEDs, and make for a much brighter lamp (as the can all be driven with the same current). If the supplier doesn't know what binned LEDs are, or can't explain it, keep shopping.

4. Marine LEDs must have a constant-current DC/DC converter drive to be efficient and give maximum brightness. If the bulb doesn't list a voltage range something like 8V-30V, or the supplier doesn't know what a PWM DC/DC converter is, or can't explain it, keep shopping.

5. Cheapo bulbs can give off UV and cheapo drive electronics can create RF/EM interference. Additional electronics can solve these problems ($). Look for a CE rating. Look also for an RoHS rating (lead-free) if you believe in a greener world.

6. Be cautious of lumen ratings. The best of class surface mount G4 LED clusters in warm white are at about 50 lumens/watt. While LEDs themselves can be rated higher, right now, when you put them in a cluster and consider the heat issues, electronics, and the packaging issues of the g4 form-factor 50/lumens per watt is about it. Measuring Lumens requires a integrating sphere and expensive equipment, so if the vendor is hip shooting Lumens and wattage, it is usually easy to smoke him out.

Watch for Practical Sailor's LED test in the November issue for a test of marine LEDs. I haven't seen the results, but I suspect that we will see that all of the companies that come out on top are owned by cruisers, and meet the criteria above. I suspect that all will be >$25 a piece as well. Also watch for the preview in Annapolis and then the introduction in Miami of a real-world 90 Lumen per watt G4 replacement with no heat sink and in an easy to fit form-factor. Hard for even me to believe, but it has some slick technology.

I will be in Annapolis with my new 120 Lumen G4s (no heat sinks or crazy wire pigtails). This bulb has no peers to the best of my knowledge, and is significantly less expensive than "the other guy"

Contact me if you will be at the show, and I will be happy to give you a real world demo.

Because this is not a commercial forum, I am not including links, etc. I will be happy to continue discussions at the request of the members.

Jeff
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Old 03-10-2008, 13:23   #32
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OK, i'd be interested in which vendors would make G4 replacements which are good. I'd also be interested if you have any ideas for easy replacements for the typical flourescent fixtures (provide output of light to a wide area such as a walkway but draws less amps like and LED). If it violates policy rules here, you can send me an email.
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Old 03-10-2008, 13:23   #33
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See also the current issue (#115 - Oct/Nov ‘08) of Professional Boatbuilder magazine:
Professional BoatBuilder - October/November 2008

Specifically “LED Lighting Matures” ~ by Nigel Calder:
Click on the 'blue' title on the front page.
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Old 03-10-2008, 14:00   #34
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How can you tell if something is ballast resistor, is there a quick check?
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Old 03-10-2008, 14:20   #35
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Gord,

That is the ONLY article I've ever seen that covers the real issues with LEDs. There are at least three other articles published in the last 2 months in major rags that, IMHO, did a huge disservice to their readers by regurgitating vendor babble, and then listing the biggest offenders as "marine" suppliers.

Cheers,

Jeff
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Old 03-10-2008, 14:43   #36
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1. If the website says 12VDC or something like 12VDC -14VDC it is likely a ballast resistor.

2. If it has a fat beige axial resistor, it is not constant current, and is resistive.

3. If it dims with less voltage and brightens with more, it is a resistive circuit. A constant-current bulb would remain at the same brightness within its range, say 8VDC-30VDC

4. If it dies quickly at 14.5V (like when you are charging your batteries) it is resistive.

5. If it is not polarity conscious, it is probably resistive

6. If it is less than $25 bucks it is probably resistive.

7. If the vendor doesn't know what controls his bulbs, he is probably selling resistive

8. If it doesn't have at least a 2 year warranty, I'd guess it is resistive.

Hope this helps,

Jeff
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Old 05-10-2008, 09:10   #37
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The Led downlighters we have made are 10 tru 36 volts dimmable warm white and 2 colors warm white and red
Unfortunately also expensive

greetings

Gideon
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Old 06-10-2008, 19:09   #38
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All I did on Santana was to just replace the bulbs with automotive LED's. USA numbers are 1156 or 1157 taillight bulbs. I have older style fixtures that use standard automotive base bulbs. The 1157 bulbs are the tail light brake light type of bulb so you can change the brightness for whatever use. They will last just as long if not longer as they are designed to be in a vehicle with all the vibration and exposure. PLUS, the won't break your bank account...
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Old 07-10-2008, 10:09   #39
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Santana,
1. It is a resistive bulb so most of your power is going to heat
2. They won't last anywhere near as long (not worth arguing about)
3. They aren't even close to being as bright as constant-current bulbs
4. High transients (up to 30V in a yacht) and charging voltages above 15V could cause a fire. Yes, LEDs can catch fire.
5. I can assure you that they aren't "designed" to be in a vehicle. Maybe "sold" to be in a vehicle. Remember the Chinese routinely sell toys and baby formula that has poison in it too. Honda, Ford, GM, Toyota, Hyundai, (in fact all OEMs) all use constant current designs. So does IMTRA, Catalupi, Hella, Aqua Signal, etc. Why, one wonders, if all they need is a ten-cent resistor, would they waste money to do that?

Like I said above. There is a large misunderstanding about LEDs, and instant-experts abound.

Jeff
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Old 07-10-2008, 10:22   #40
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I've never seen an LED catch fire before, but in College during my circuits class we used to increase the voltage quickly which would blow their tops relatively dramatically. I've only ever seen the LEDs release their magic smoke when they're overpowered, not actually burn.
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Old 07-10-2008, 10:25   #41
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LEDs

Jeff,

Okay, I'll admit it, can I get a copy of your white paper, LED's for dummies??

thanks!
-dennis
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Old 07-10-2008, 11:35   #42
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LEDs on fire:

Costco White LED lights catch fire! | apeman.org
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Old 07-10-2008, 11:48   #43
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Quote:
Originally Posted by Force Majeure View Post
According to what I just read about that it wasn't the LEDs catching fire, it was an electrical problem. It seems like this is not a case of actual LEDs catching fire, just crappy electronics catching fire.

Costco LED's Recall - Forums of PlanetChristmas

Quote:
Now my experience with them YES THEY DO CATCH FIRE!!!!!! I have 7 set that have caught fire near the plug.
http://www.hardcoreware.net/forum/le...ng-t25411.html

Quote:
MONTREAL (CP) - Universal Lights has announced a voluntary safety recall of exterior LED type white and blue Christmas lights, manufactured by Bortex.
The lights are being recalled because of an electrical problem. No personal injuries have been reported. The products involved were sold between August and December 2005 at Costco Wholesale warehouse locations in Canada (product Nos. 501701 or 501702), in packs of three boxes.
I just looked around quite a bit and can't find a single instance of LEDs catching fire. I'm not saying that you're lying of incorrect, I'm genuinely interested in your claim and I'm looking for some proof to back up your statement

Cheers!
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Old 07-10-2008, 11:52   #44
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That wouldn't be the first time that "christmas lights" usually from China came into the US with outright counterfeit safety approval labels on them.

The other day I woke to the sound of a small nearby explosion, the kind of thing you really don't want to wake up to. Looked around, couldn't see any problem, couldn't see any smoke. Got a cup of coffee and washed my eyes...and saw a common 9-volt Duracell battery with the bottom of the battery blown off and scattered debris behind it. The battery should have been dead (it had been running a fan until it ran down and was unplugged the day before) and playing dead very politely, but apparently it went manic and blew up!

Penguin on the Telly syndrome?
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Old 07-10-2008, 12:45   #45
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I just Googled to see what I could find and posted that link. Maybe it isn't a good example, but I don't know what cause the short. A melted LED will definitely cause a short.

Having said that I have seen cheap LEDs in a smoldering burned-out mass. While I wasn't there to witness it, here is what happens: Say you have a cheapo LED regulated with a resistor sized for 12V (autostore bulb), and you are equalizing your AGMs at the recommended 15.5V. In this scenario, the input voltage increased 30%, BUT, because of the voltage drop of the LEDs themselves, the current jumped more like 40-45% over the design threshhold. To illustrate how heat sensitive the PN junction is, there is a rule of thumb that for every 10 degrees C increase in junction temp, you halve the life of the LED. The junction overheats quicky with over-voltage, and like a regular diode, it can fuse the die and then the wires heat up. It is the luck of the draw after that. Because standard LEDs have such fine legs, I would bet that more often than not they act like a fuse and break into an open circuit (just like what happens to the diodes in your alternator). I haven't Google diode fires, but I suspect that would result in more hits.

Jeff

I wish I hadn't just tossed the burned up bulb that a customer sent to me or I could have sent you a picture.
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