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Ron Boyd

Full vs.Half wave LED's

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dariansdad wrote:

I have two questions then.

Who is CDI?

What are "snubbers"

Oh, and thanks for the replies. Merry Christmas everyone.


This was already answered but since this recently came up on another site and I created this Wiki for it. I thought I would post it here so others can see, and correct if I am wrong :P

[urlhttp://www.controlbooth.com/wiki/snubber]

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I agree with Orville.

Retired now from 50+ years in electronics and loved LED's the first time over 25 years ago.

Now what your lag issue is that LED's fade differently than Incandescent. LED's will turn on and off much faster than minis also.

My first year using LED's in my display showed this trait. If you connect some LED strings to your controller and using one of the Hardware utility programs to manually check the light string, you will see that your eyes will not see much change in the intensity of the LED's once your reach about 70-75% intensity. Do this in a darkened room.

An intensity might be in the 15-30% range for a half intensity with lower intensities down to 1%. Even use 1% on during the Macarana Christmas Song.

This could be your lag problem on fades up or down as you are spending 1/4 of the fade time to a level that your eyes will start seeing the fade then it a slow to fade at that point because the LED will stay on longer brighter than a mini.

By adjusting your maximum intensity and other levels of lower intensities you will find your sweet spots to make them operate the way you want.

Fast songs like WIW will like LED's as we can really make a fast blinky display, even at 100% intensity. More WOW than minis can do. Slow songs need more attention to the fades.

This is just my experience using 95% LED's in my display for the past 3 years.

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Orville wrote:

Mark Belgen wrote:
Please also be advised that what no one has addressed is that LED's have a fairly significant response lag time that incandescent bulbs do not have. It can be a serious problem if you have a musical piece that is very quick in transition that you are timing your lights to or if you want a very precise lighting action. :{ It has to do with diode "biasing", which I won't get into detail with.

Should you create an LOR show using incandescent light strings and then replace them with LED's, be prepared for timing issues that may force you into adjusting the timing of your shows.

I personally have not seen the financial benefit of LED's as my lights are not on long enough to realize any real cost benefit. LED's are great for sustained lighting where they will be on continuously for long periods of time. The cost of LED light strings are really prohibitive for me in today's economy as they are higher in cost, I get fewer lights per light string and they are not on long enough for me to realize any cost benefit. Plus, the reliability is just not there for LED's as well.

As an Electrical Engineer, I know all too well the limitations of LED's in the application in which we are attempting to use them. What they are great for are mutlti color single strings in which address busses control the LED color & intensity, like the CCR, but you will pay dearly for these as well.

For most light strings, I recommend that you hold on to your incandescent light strings for as long as you can, with the exception of blue colored lights as their color coating breaks down the fastest on the bulb and it may be cost effective to go LED for just those.


Well I have to disagree, I changed from Incandescent to LED WITH NO TIMING ISSUES, Nor did I have any "lag problems" that you're describing and I'm using quite a few very fast TSO music in my display. I just swapped out the LED string for an Incandescent and have had ZERO issues.

They have even CUT DOWN the cost of my power bill, they may not be on all the time, but they have saved me over $150 in power consumption as opposed to when I had all incandescents. I still use incandescents for blow molds currently, but I've been seeing new technology in LED Lighting that is going to be very possible to remove all incandescents from my Blowmold items and go LED. I've seen some extremely bright LED bulbs lately, but since these are also "NEW" to the market, they are overpriced (my opinion).

But when they start coming down to a reasonable price, my incandescent bulbs will become a thing of the past and will be replaced with LED bulbs. I passed by an LED Security Light fixture in Lowes the other day, when that thing came on it was BRIGHT, too bright, I had to put my sunglasses on because of it. I thought they look like LED's but can't be, when they finally turned off and I could look at them, I was surprised they were LED's, but they were the brightest of any I'd ever seen. I do have some LED bulbs I use in the home because they put out a nicer ambient light than an incandescent bulb.

I was in the electronics field for over 40+ years, and I just can't agree with you on LED's, been using them for years in my model trains as headlights, have never had one go bad, never had one with any sort of lag time as you state. If there is a lag, it sure isn't that noticable, and I've yet to see it.

Last year I converted about 80% of my lights to LED. I realized a savings of about $150 in less electricity used for the month the lights were on. However, that was not the reason for converting to LED. The main issue that drove me to LED was I was going to have to install more circuits to run all the lights. I keep hitting up against the maximum amps on each LOR box and each electrical circuit. LED lights solved the problem for me and I haven't looked back. This year I will be 95%+ LED.

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CKSedg wrote:

The main issue that drove me to LED was I was going to have to install more circuits to run all the lights.

Very true. The price of electricity pales in comparison to the price of upgrading your electrical service and installing additional circuits.

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Gentlemen, you will find that if you include the additional cost of the LED's to your cost savings calculation, you won't be saving money until after you clear the Break Even Point from the additional cost of the LED's, which for me takes all of December as my shows' duty cycle averages around 20%.
And you will pay more for brighter LED's. The Ultra Brights that you are talking about in Traffic Signals are very expensive.
You may not notice or perceive the response difference, but I have tested these using an O-Scope, so I have data to support my claim. Due to the lag in the energizing of the transformer and rectifier, the bias time for the diode, the lag time difference tests out to be on average .462 sec., and that's with a full-wave LED, so it will be much longer for a half-wave.
Now you may perceive this as no lag time, but in reality, there is a lag time.
I can send you the test setup and my data results if you are interested.

And FYI - I have a BS in Electrical Engineering from CSU Long Beach and a Masters from USC with over 20 years of experience, so I do have some competency in this subject.
And price reductions over time may not be that significant due to "economy of scale" reductions as you might think, because some of the required materials used in the production of these LED's are precious metals. And as you may already know, precious metals don't tend to go down in value over time and there is currently a shortage of silver and nickel, which causes the price to go up even more.
Just ask Dan, his per light unit cost (SMT LED) for his CCR is significantly greater than the per unit cost of an incandescent bulb. That's why the cost of the CCR product is so high. And for my reasons stated above, it will not be coming down in price, it will continue to go up.

Don't miss understand me, your opinions are great, but they are after all just opinions. I am just trying to educate people in this forum with the facts (data) so that they can make an informed decision. :)

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I have all kinds of LED. It has never been a big deal to me or anyone looking at them. I buy my lights at walmart, lowes, and home depot. I would not worry to much about it.

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Saving money on electricity was NOT the reason I went to all LEDs.

Durability and reliability were my reasons. Pull them out of storage, hang them up, and they work, year after year.

I hated having to spend the time to trouble shoot strings of incandescent lights when they came out of storage and didn't work. (yes, I had the LKP and the buzz box)

I also hated having to go out in the cold during the display season to replace burned out or broken bulbs.

Been a happy LED user since 2007 with no failures in the field and have over 700 strings (did have one, only one, string that was DOA. Paul at CDI promptly replaced it.)

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I wnt to leds because they are a true color, will save me $$$ in the long run (let us know how often you replace your incans to our leds). Also, no color fades of the bulbs. I rarely have been able to reuse green or blue. They are always faded. Not to mention, I haven't had much luck with incans outside for multiple years. Maybe two at most, and thats been clear lights. Now inside is a different story. I can get two years out of colors inside (blue fades inside, too). Not to mention how the incans bulbs break a lot because they're glass. You pretty much have to purposefully try to break a bulb on the type of leds I have (CDI all the way!) I even bought the top of the line. Those got replaced mid season. So you take the cost of a decent incan, that are rated for around 3,00-4,000 hours (correct me if I'm wrong, if so it is only give or take 1000 hours), to my leds rated at 50,000 (that is not a typo) hours. Thats 10-12 times longer than yours. So even if you buy the wally specials at $2.50-3.00/ box, I will take the $10-14 cost of my leds, to the $30-36 of incans. Now that is per string. Now multiply the $16-20 difference times the amount of strings used. So, whos saving money? Not to mention the subtle savings ove the seasons on elec. It may not be huge, but it'll buy me at least three cases at the end of their lifetime. But thats just my feelings and opinion on the matter. And I didn't go to college. Didn't need to to figure this out.

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I also hated having to go out in the cold during the display season to replace burned out or broken bulbs.

"Like"...haha, so agree, for a couple reasons. Don't want to be in the cold freezing my fingers off, thats why I hang in Sept and early Oct.
Second, it ruins the snow in my display!:D Footprints = :X

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I added about 80 warm white strings (out of about 900) to my display this year and here is my review so far.


Pros:

  • Less power
  • Looks great like a clear mini at 100% on
  • M6 is a bit larger than a mini
  • Durable saves time troubleshooting
  • Less bulky extension cords :)


Cons:

  • 4" spacing makes things look sparse compared to minis
  • Don't fade near as well (longer fades)
  • Had one strings where the case broke and and one broken wire


I think in the end, both look great, but when you mix them, both show their distinct characteristics; good or bad.

In the end, I would be happy with either, but I would prefer not to mix them. Will my guests see the difference? Probably not.

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JBullard wrote:

Saving money on electricity was NOT the reason I went to all LEDs.

Durability and reliability were my reasons. Pull them out of storage, hang them up, and they work, year after year.

I hated having to spend the time to trouble shoot strings of incandescent lights when they came out of storage and didn't work. (yes, I had the LKP and the buzz box)

I also hated having to go out in the cold during the display season to replace burned out or broken bulbs.

Been a happy LED user since 2007 with no failures in the field and have over 700 strings (did have one, only one, string that was DOA. Paul at CDI promptly replaced it.)


In addition to all of the above, as well as decreasing the electrical demand that would have exceeded my 150 amp panel capacity, my primary issue was fading of colors, requiring in the old days staining the incandescents with glass stains every 2nd or 3rd year (a big job when you have 100K plus of lights). LEDs don't fade, and the color is generated by the LED itself (although granted many add colored lenses as well). That alone was worth me switching, and I haven't looked back since.

The colors are much more vibrant than incandescents are, leading to a neon look that some hate, but some love.

I have been using LEDs since they first were introduced to the decorating community in 2005. The only failures have been a few DOA strings (due to poor manufacturing of the socket connections) that have been replaced no questions by the vendors!

LED vs incandescent is like the CD vs vinyl LP issue, everyone has their opinions or "facts". There is room for both, that is until the government makes a decision to lower energy cost by eliminating sales of the heat generating, inefficient, century plus old designed incandescent light bulb.

Greg

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I see prices coming down all the time on LED lights as the demand grows, prices normally go down, not up.

The newest technology LED's are expensive, but the older ones have dropped in price, which we know will eventually be phased out for the newesr technology version.

As with anything, once it comes out, it's usually OVERPRICED, but eventually DOES COME DOWN in price, may take a while, but I've yet to see anything stay at the same price since it's inception. Even those Mr. Christmas boxes have come down from what they were initially. I recall them being somewhere around the $299+ when they first appeared, bought one (which got me started in this crazy hobby) on Sale at K-Mart for $159.00 (regular price at the time was $199.95) a few years after they'd been around awhile, now I think you can get one for between $129-$149 normal price, and possibly even cheaper on line somewhere.

So I don't beleive LED lights will always be expensive and I beleive they will come down in price, I've already seen lower prices on some of them this season at regular pricing in most Big Box stores.

As for lag, again, I've never noticed, not even on many of the SLOW songs I'm usuing like Stille Nacht or Home on Christmas Day where I use slow fade effects in some areas of the songs or when the lights slowly fade out to black at the end of most sequences.

Sure an oscilliscope can SHOW YOU things the human eye can not discern, so in that respect, sure you may see a "lag time", but I'd wager 100% of the human populous will never see this lag time in any of our displays. I've used oscilliscopes and other test equipment being that I've worked in Prototype Engineering labs, Technician Labs and such, so I do understand what you're looking at, but it's my opinion MOST decorators don't have this type of equipment to discern these "invisible to the human eye" lag times this equipment can pick up and show you.

Of course just my opinion.

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@ Orville...I saw the Mr Christmas box a day or so ago, for $99 regular price. I remember when I was looking a few years ago and they were $250.

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Mark Belgen wrote:

Please also be advised that what no one has addressed is that LED's have a fairly significant response lag time that incandescent bulbs do not have. It can be a serious problem if you have a musical piece that is very quick in transition that you are timing your lights to or if you want a very precise lighting action. :{ It has to do with diode "biasing", which I won't get into detail with.

Should you create an LOR show using incandescent light strings and then replace them with LED's, be prepared for timing issues that may force you into adjusting the timing of your shows.

I personally have not seen the financial benefit of LED's as my lights are not on long enough to realize any real cost benefit. LED's are great for sustained lighting where they will be on continuously for long periods of time. The cost of LED light strings are really prohibitive for me in today's economy as they are higher in cost, I get fewer lights per light string and they are not on long enough for me to realize any cost benefit. Plus, the reliability is just not there for LED's as well.

As an Electrical Engineer, I know all too well the limitations of LED's in the application in which we are attempting to use them. What they are great for are mutlti color single strings in which address busses control the LED color & intensity, like the CCR, but you will pay dearly for these as well.

For most light strings, I recommend that you hold on to your incandescent light strings for as long as you can, with the exception of blue colored lights as their color coating breaks down the fastest on the bulb and it may be cost effective to go LED for just those.

Use LED and incandescents side by side on the same channel and notice no difference in timing.
I agree that LEDs won't typically be cost effective from an electricity use standpoint for the average Christmas display user (especially a non-static display). However, I had maxed my power availability for outdoors, or for my house for that matter. I found that it was cheaper to start switching to LEDs rather than upgrade my electrical service and and a subpanel. Particularly found that getting LEDs on clearance after Christmas aided this as well.

Agree also that blue (and green) incandescents don't hold their color for much more than 1-2 seasons so LED's are the way to go especially with these colors.

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This is an interesting message thread - with a lot of mis-information.

There are those that don't like LEDS because of their brightness and color saturation, that is a preferance.

Fact, using a Kill-O-Watt meter, a string of 100 mini-lights uses 97 watts, a string (depending on color) of 100 LEDS uses between 3 and 4 watts. How can you say that there isn't a cost savings?

An incadescent light will take milliseconds to get up to tempurature, an LED "lag time" is in the nano-second range.

As for the 1/2 wave or full wave rectifier LEDS, full wave is better - lights are on full time and look brighter.

I use both, the 1/2 wave are cheaper and I get them from the Big Box stores. My full wave LEDS are from Creative Displays, they are a better quality, and they work with LOR.

Last year I bought a bunch of the Martha Stewart LEDS from Home Depot - they are total crap. They don't fade and you need a snubber or they stay lite.

If you have part of your display in constant motion - don't use 1/2 wave LEDS there - there will be the 30 hertz flicker - but wait, your TV is updating it's screen at 24 hertz... flicker?

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sjmiller wrote:

This is an interesting message thread - with a lot of mis-information.

...

Fact, using a Kill-O-Watt meter, a string of 100 mini-lights uses 97 watts, a string (depending on color) of 100 LEDS uses between 3 and 4 watts. How can you say that there isn't a cost savings?
...

The point that I think some are making is that it will take many many years for the cost savings from lower electricity use to exceed the price jump of buying LEDs--Return on Investment (ROI) basically. If basing purchase purely on this, it is a gamble that it may pay off. This is why I mainly buy my LEDs when on sale/clearance. Plus the table tilts when factoring in house electrical upgrades that may be needed.

Over the years, it seems that majority of light strings (LED or incandescent) fail due to cheap wire issues not actual bulb issues. So a LED that lasts a 1000 years doesn't matter when the wire fails in 3. Now I don't know if LED strings wire become less "fragile" or brittle over time since they don't experience as much heating and cooling due to less electrical load on the wire.

All I know is that it sure would be nice if the price of LEDs would come down like we predicted/hoped that they would several years ago, but in these days of ridiculous inflation just the opposite is happening. For example, 60ct strings have now become 50ct strings for the same price (reminds me of the subtle deception of Americans with smaller ice cream containers or cereal boxes).

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Old topic but let's bring it to the top of the stack.

I took a totally different approach to driving LED for my HolidayCoro faces and other similar props.

I'm not using a LOR AC controller but instead I'm using a CMB16D-QC. I'm using modified AC half wave strings I got from BigLots!. These came as two 60 LED strings in a box that I got on a sale day for about $8.50 a box. That's 120 LED. The modification is quite easy, you cut out all of the traveler wires leaving you two 30 LED long string. Now for installing and driving them.

First I'm powering the CMB16D-QC from a 48VDC power supply.

I run 15 LED in series and then parallel those strings. Note, you need to put at least a 1 ohm resistor in series with each strings as paralleling LED can cause problems with out that resistor. With 15 LEDs and 48 volts the LED will run at about 16ma which seems to be bright enough for singing faces. If you want them brighter then run 14 LED with a correctly sized resistor so you can run at their rated 20ma.

On faces you going to find many places when you need less than a 15 LED so shorten up the string at needed and select the correct resistor.

I like this much better from a safety point of view. If you use a good 48VDC power supply and make sure it's fully grounded you virtually eliminate any shock issues and you can run in full raining conditions.

Dimming is much better than with the AC controllers although I will say that LOR does need to adjust the PWM curves on the CMB16D-QC. You should be able to dim all the way down to 0 but currently the 1% setting is brighter than it should be. Remember you always sending the LED full voltage just making the pulse very narrow. I plan to call LOR about this and see if they can update the firmware so the dimming will be better.

Have fun.

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Timon wrote:

First I'm powering the CMB16D-QC from a 48VDC power supply.

... the 1% setting is brighter than it should be.

That is impressive! :P

I have also found that 1% is too bright when using a DC board with a 12v RGB ribbon. I'm still waiting for the new firmware with the dimming curves.

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Not an electrician and I am Budget conscious So I went 100% LED and striclty from Big Box Stores for the last 3 years. Purchased most of my lights from Walgreens and Target and they are probably Half wave.I did have an issue with Fading on certain channels if I overloaded them with to many light strings but that was easily fixed with a snubber of some knid. (Glade air freshner)I have not had to replace any sets of lights yet after 3 seasons but I expect that at some point that will change. I just can't see spending $15-$18 per set when I can but 3 sets for the same price and have plenty of spares to use as replacements. I use Red, Green and Blue and they all work the same for me.

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