LED Technology for refit to Existing flourescent Lighting

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mefalk55

Member
Hello Guys, Soon I will be starting the daunting task of retrofitting flourescent fixtures with LED bulbs. Are the ballasts bypassed and the new LED bulbs connected to the 120V line? Or is the ballast still used? I kinda find it hard to believe that this high voltage will be used for the new LED bulbs. Any information will be appreciated.
 

mefalk55

Member
LED Technology

LED Technology

Hello again Guys, I guess alot of you are not familiar with this new LED Technology either...... At first I thought my boss was pulling my leg on this job. But, yes it's true. Light Emiting Diode bulbs to replace standard flourescent bulbs. Efficiency is the key word here... 70,000 hours of life at a fraction of the cost to operate. I hope I did not stump you guys. This is not just a silly question. Any help would be appreciated. Even if you have an idea as to who I can inquire to would help. Thanks again.
 

jdsmith

Senior Member
Location
Ohio
Can you post a link to the products you are using? As far as I have heard, T5 fluorescents are more efficient than most LEDs so LEDs are only a realistic option for special applications. Namely in-ground fixtures that aren't quite as waterproof after changing bulbs, or where changing colors are desired. I know this won't be true sometime in the future, and maybe it's already outdated information.
 

LawnGuyLandSparky

Senior Member
Problem with the claims by LED manufacturers is not that the LEDS actually last longer or save energy, but the circuit boards and other necessary components are nowhere near as durable or reliable.
 
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Lxnxjxhx

Guest
LED Technology for refit to Existing flourescent Lighting

LEDs are driven by DC current, 10 mA on up, and the voltage required to achieve this rated current is not controlled in the manufacturing process but is typically somewhat more than 2 volts or so.
You could use a diode and dropping resistor to light these things off the AC line, but they probably use more sophisticated ways to drive these things.
You have a make and model for the replacement devices you're going to use?
 

catchtwentytwo

Senior Member
mefalk55 said:
Hello Guys, Soon I will be starting the daunting task of retrofitting flourescent fixtures with LED bulbs. Are the ballasts bypassed and the new LED bulbs connected to the 120V line? Or is the ballast still used? I kinda find it hard to believe that this high voltage will be used for the new LED bulbs. Any information will be appreciated.

I too would like to see some information on the product you will use. Best I can find is this patent http://www.google.com/patents?vid=USPAT6739734

(BTW, check out the inventor's name) :grin:
 

Mr. Bill

Senior Member
Location
Michigan
I'm sorry but I keep thinking that someone bought a sales pitch. I think the customer will be disappointed with their first electric bill afterwards. For just general, ambient, office lighting, nothing is better then a T8 lamp with an electronic ballast. Yes, not even T5's are more efficient yet. The benefit of T5's is that the light can be controlled better because of a smaller source area.

F32WT8
Average Life: 20,000 hours
Initial lumens: 2950 @25C
Maintained lumens: 2714 @25C
inst-start Ballast watts: (2-lamp) 59W
Ballast factor: 0.90
maintained lumens per watt: 82.80 lm/W

F54WT5HO
Average Life: 20,000 hours
Initial lumens: 4400 @25C
Maintained lumens: 4136 @25C
prog-start Ballast watts: (2-lamp) 117W
Ballast factor: 1.00
maintained lumens per watt: 70.70 lm/W

F54WT5HO
Average Life: 20,000 hours
Initial lumens: 5000 @35C
Maintained lumens: 4650 @35C
prog-start Ballast watts: (2-lamp) 127W
Ballast factor: 1.00
maintained lumens per watt: 73.21 lm/W

White LED
Average Life: 50,000 hours
maintained lumens per watt: About 65 lm/W right now. The Generic LEDs are going to be lower. Laboratory tests have gotten LEDs well over 100 lm/W but I just haven't seen them out in the market yet. But every 6 months the top end LED manufacturers keep dramatically improving their products with higher outputs and efficiency so it might not be long before they pass flourescent. But then you have to justify the cost.

To the original post, you'd need check with the manufacturer as others have stated. My guess is that you would need to by-pass the existing flourescent ballast. The LED's should have their own driver to change the line voltage to a usable level for the LEDs.
 
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Lxnxjxhx

Guest
LED Technology for refit to Existing flourescent Lighting

LEDs vs. Flourescents.
Since LEDs come in red, green, blue, and other colors, you should be able to simulate the daylight spectrum or almost any other spectrum very accurately. I guess some applications would even want to vary the color (cool white to wake up employees in the morning and warm sunset colors at quitting time). E.g., I'd think grocers would want this kind of spectrum flexibility to put their products in a good light (sorry, I couldn't resist).
 

ZZZ

Member
Manufacturers of some refrigerated cases started using led tubes 3-4 years ago. It is not for long life, but less heat load in the cases. The cost is high. They will not replace fluorescents for at least 5-10 years yet, IMO.
The only times we retrofit to T5 instead of T8 is for HO fixtures where we can't get enough light from T8's. Of course if you can stand less lumens, then replace the T12's with T8's.
I think the question was a sales pitch as the lamps are available to work with existing ballasts. Oh, did I mention EXPENSIVE? $149.00 each.
 

mdshunk

Senior Member
Location
Right here.
As must as I think the opening post smacks of spam, I am willing to say that we're way way off from retrofitting T8's with LED's for a variety of reasons. #1 is installed cost, and #2 is life cycle cost. The early LED exit lights are failing with great regularity.
 

tom baker

First Chief Moderator
Staff member
Mr. Bill said:
I'm sorry but I keep thinking that someone bought a sales pitch. .
Wall Mart is changing out the fluorescents in their reach in cooler cases for LED. One of the big advantages of the LEDs for this application is they do not generate heat that has to be removed, plus the long life, plus the energy savings.
Wall Mart also wants to be a leader in sales of CFL. As price driven as WallMart is they would not do the LED retrofit if it didn't make sense for their stockholders.
 
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Lxnxjxhx

Guest
The early LED exit lights

The early LED exit lights

I'm surprised that they're failing. Maybe they are overdriving them, trying to get more light to meet some spec. Also, they might work better on smooth
DC rather than filtered DC from a switch mode invertor.

In electronics they don't even put them in sockets because of the long service lifetime. They're good for auto electronics because they don't care about vibration, but they may have the same invertor problem or transients from the alternator.
 

Mr. Bill

Senior Member
Location
Michigan
tom baker said:
Wall Mart is changing out the fluorescents in their reach in cooler cases for LED. One of the big advantages of the LEDs for this application is they do not generate heat that has to be removed, plus the long life, plus the energy savings.
Wall Mart also wants to be a leader in sales of CFL. As price driven as WallMart is they would not do the LED retrofit if it didn't make sense for their stockholders.

I believe that LED lighting has it's place. Reach-in cooler cases is one of them. Electronics operate better in colder temperatures than fluorescent. Decorative lighting, task lighting, outdoor or inaccessable lighting are other spots for LED use. But they do generate heat like all lighting does based on wattage. If you need to light something that is really temperature sensitive then I think fiber optics is best since the heat source is remote. But then your efficiency goes down the drain with fiber. Everything has positives and negatives. There is no perfect light source that will solve everyone's needs.
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
As Mr. Bill mentions, LEDs put out quite a bit of heat.

At the present time, the very best LEDs in the lab have higher reported efficiency than the very best T-5 lamps that you can buy, in the 100 lumen per watt range. I take both numbers with fairly large grains of salt, but it gives you an idea of the comparison.

What this number means is that when you put 1 watt of electricity into the lamp, you will get roughly the _same_ amount of light out, with the rest going to heat.

Where LEDs have gained the reputation for not producing any heat is the fact that most LEDs are used at very low power levels; say 1/20 watt or so. But if you've ever dealt with a high power LED operating at 1 or 5W, you know that they can get quite hot.

LEDs have some characteristics that make them very useful for many applications. In many ways, they follow different 'scaling laws' than most other light sources.

LEDs can be easily and efficiently dimmed. Generally, LEDs get _more_ efficient when dimmed, not less. Contrast this with most other light sources when dimmed!

LEDs can be easily manufactured to operate efficiently at very low power levels. A 1/20W LED will be very efficient; but you won't be able to get 1/20W T-5 :) At low power levels (below 1W), LEDs are easily the most efficient light sources available.

LEDs become more efficient at low temperatures. This is probably a big win in a cooler; the efficiency and light output of the LED will go up, that of the T-5 will go down. But the downside of this is that LEDs cannot tolerate high temperatures. While a 32W LED and a 32W T-5 might generate the same number of watts as heat, the LED will require extensive heat sinking in order to keep the junction temperature low.

LEDs are _very_ expensive compared to other bulk light sources, though the price is coming down all the time.

-Jon
 

Steve-R

Member
Mr. Bill said:
For just general, ambient, office lighting, nothing is better then a T8 lamp with an electronic ballast. Yes, not even T5's are more efficient yet. The benefit of T5's is that the light can be controlled better because of a smaller source area.

T5 lamps are definately more efficient that T8s. T5HOs are not. A 28W T5 provides about 10% to 15% more lumens/watt maintained than a standard T8.

LEDs, in my opinion, are a gimmick so far. No one is even approaching the efficiency of a T5 with any production LED lamp that I've seen, much less surpassing. I keep getting architects in my office telling me how efficient LEDs are...then when I show them that none are close to the lumens/watt of a T5, they are suprised. Lighting reps tout LEDs as super efficient. Sure, they are efficient compared to incandescents, so if they had reached this stage say 60 years ago, they would've been a great development, at that time.

Today, LEDs appear to be snake oil as far as efficient primary light sources are concerned. Hopefully that will be a different story in a few years, but so far they aren't developing as fast as I expected. Two years ago from what I heard from the manufacturers I was thinking maybe they'd be there in five years, but now we don't seem much closer than we were two years ago.
 

sparkfree

Member
speaking of retrofits progress has a new line to replace p-8 trims with led's. also have cove lighting which is really slick,but it comes with a high price tag. anyone used any yet? we just quoted some for a high ceiling. the p-8 are about 130.00 each
 

Mr. Bill

Senior Member
Location
Michigan
Steve-R said:
T5 lamps are definately more efficient that T8s. T5HOs are not. A 28W T5 provides about 10% to 15% more lumens/watt maintained than a standard T8.
I still think a T8 lamp is more efficient.

Mr. Bill said:
F32WT8
Average Life: 20,000 hours
Initial lumens: 2950 @25C
Maintained lumens: 2714 @25C
inst-start Ballast watts: (2-lamp) 59W
Ballast factor: 0.90
maintained lumens per watt: 82.80 lm/W
F28WT5
Average Life: 20000
Initial lumens: 2610 @25C
Maintained lumens: 2427 @25C
prog-start Ballast watts: (2-lamp) 62W
Ballast Factor: 1.00
maintained lumens per watt: 78.29 lm/W
 
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