# Three ways to do a 48 inch LED Tube Retrofit



## Black Dog (Oct 16, 2011)

John Peters said:


> There are three ways that you can retrofit an old fluorescent fixture with
> new LED tubes.
> 
> (1) There are tubes that work with the existing ballast. They are plug and play but I wonder if the ballast is wasting some electricity and of course when the ballast fails then we still have to do some rewiring.
> ...


What is your question?


----------



## John Peters (Jan 1, 2009)

Does it waste electricity to leave the ballast in the circuit using method number (1)

Does anyone have experience in determining which way is the best one?


----------



## aftershockews (Dec 22, 2012)

So if I get this right. You installed some LED lamps that are to work with existing wiring for T8 ballasts?


----------



## The_Modifier (Oct 24, 2009)

aftershockews said:


> So if I get this right. You installed some LED lamps that are to work with existing wiring for T8 ballasts?


If so, I believe they may be referring to *THESE* aftershockews


----------



## chicken steve (Mar 22, 2011)

I'm finding many biz owners wanting retofits also wanting to change out elements themselves. And why not?, changing a tube does not require our services. 

But i also am finding they'll stuff anything in that fits. Like the lady who fried her 150W MH fixture stuffing in a 100W A bulb.

So my Q aside from the OP here is, if a portion of old style unshunt fixtures exist with the new rewired shunted retro's , is it a recipee for a similar disaster?


~CS~


----------



## NacBooster29 (Oct 25, 2010)

I just put a few hundred replacement fixtures in. They were all new fixtures. They had led ribbons mounted above the diffuser. 
With a driver in a small compartment. They use a fraction of.the power of the old t-8's.

I have used the tubes before and the light wasn't as bright as these models. 
Just my .02


----------



## sbrn33 (Mar 15, 2007)

I also would replace the whole fixture whenever possible. Better distribution and newer looks.


----------



## Electric_Light (Apr 6, 2010)

Many rewire type LED tubes produce unacceptable amounts of flicker that is far worse than HPS or magnetic ballast T12 systems. Many don't add flicker in product selection criteria and its not really a common specification standard. Flicker is extremely annoying to occupants. 

I like the idea of adding these two lines
"percent flicker shall be less than 10% 
flicker index shall be less than 0.02"

If the existing T8 electronic ballasts are compatible, drop-in do not make flicker any worse since the ballast functions as the driver.


----------



## ecelectric (Mar 27, 2009)

I've used the 120 volt ones you mentioned . Just wire line voltage to tombstone in one end and cap off the other end . Lights are bright and work great , they even give you a ticket to put on the fixture after to let future installers know the fixture has been modified . The bulbs are 4 footers and cost $25


----------



## Electric_Light (Apr 6, 2010)

*Payback period. Something that doesn't exist for retroftting super T8 to LED.*



ecelectric said:


> I've used the 120 volt ones you mentioned . Just wire line voltage to tombstone in one end and cap off the other end . *Lights are bright* and work great , they even give you a ticket to put on the fixture after to let future installers know the fixture has been modified . The bulbs are 4 footers and cost $25


DLC qualified at the minimum. 
Refer to the graphs I posted and insist on less than 10% flicker and less than 0.02 flicker index. 

Off the chart flicker contents is a new problem brought on by Light Emitting Decorations. It's not included in product specs since there's no mandate on meeting a certain value. Hopefully Energy Star will update the requirements for label qualification. Many "rewire" type LEDs often use the AC module design that flicker like no other and produces arguably the worst possible quality light. Worse flicker than HPS. Worse than magnetic ballast T12. Some may have a decent driver that do not flicker much. You'd have to try a sample. http://www.ledsmagazine.com/article...sign-eliminates-led-light-strobe-flicker.html

Nothing personal, but "brightness" is not an acceptable metric of evaluating performance. Lighting is art and science, but this portion of it is science. Our eyes are not straight responding. Instead, they have an exponential curve called the "square law" which just plays out in favor of LED sales reps. If the measured light level drops to 70%, the perceived brightness is 84%. If it drops to 50%, it's perceived as 71% as bright. The reason for this is because our pupils are always adjusting dynamically. If you toggle between 3, 2 and 1 blubs of the same output, the output is 100, 67 and 33%, but they're perceived as 100%, 82% and 58%. So, you can see how it creates an illusion of efficiency. 

Anyone familiar with photography knows that when current lighting gets you a perfect exposure at f/4.0, you can get the same exposure with 1/4 the light level by widening the aperture to f/2.0 but in doing so, you decrease the depth of field especially in the up-close range. If you're looking at 10' or further away, this effect matters less. A proper ambient illumination level along with task lights as needed are essential where occupants constantly need to focus in the in-your-face to an arm's length away range. 

Have you noticed lighting design is generally done using maintained lumens, but the LED sales industry is obsessed with initial lumens out of the box? Maybe it has to do with the fact that super T8s are proven to hold 90-95% of initial output from the time it comes out of the box until it burns out while the LEDs are generally rated for hours of use until degradation to 70% of output. They're regularly exploiting unnoticed output loss to get the kW drop he wants in order to get the dollars of power bill savings and a presentable payback period figure so they can justify the pointless installation. They often justify poor performance using non-sense subjective perception such as how bright it seems, taking a FC measurement at one point and conveniently dismissing the lacking illumination on other surfaces as "wasted light that wasn't needed". 

Another efficiency perception exploited by LED sales people to justify reduced output as "efficiency gain" buy using a high CCT LED such as 5700K rating which is bluish white and gives a perception of higher brightness at lower illumination levels. This method is not industry accepted for compensating inadequate performance. IESNA does not recognize it.

In the past, lighting designers gave very generous allowance for lumen loss. If lumen maintenance was assumed at 80%, the system was aimed to provide 1.25 times the target level. (1/0.8 = 1.25). A huge chunk of energy savings from lighting "upgrades" come from trimming the excess fat. That's not what LED sales people will tell you. 

There's no such thing as payback period in doing LED retrofits on modern lean design T8 systems. The initial overlighting is much lower. The Lumen loss compensation is far lower by using values that is in line with office space fixtures using parallel wired lamps and decay factor fitting RE80 lamps.
Not the LLF you'd use for series wired (one bulb out = two goes dark), F40T12 lamps in a cement plant. There's no fat to trim off to create an illusion of LED savings. 

Given a foot candle target of 50 and a minimum maintained level of 45 using LEDs rated at 50,000 hrs to L70, you need to design to 64FC. (45/0.7=1.43) If you don't, the system doesn't perform as it should. Only HIDs and LEDs have such a huge depreciation. :laughing: Lighting up to 64FC when you only need 50FC wastes power. You can avoid this by a costly active compensation setup that dims during the earlier portion of life and compensate upwards to maintain 50FC (which is how electronic HID ballasts save energy...) or you can use products that don't suck so bad. The greater the lamp depreciation, the more aggressively you have to oversize initially. 

Some CREE LED architec. grd fixtures are L90(time it takes to drop to 90% of initial output)rated to 50,000 hours, *but boy, they're so expensive*. The L90 rating finally put LEDs in the same playing field as 68-80K hour 2XL life super T8s relamped at 70% of rated life (A tad over $6/lamp).

Today's high efficiency T8 systems can *maintain* 80-90 lumens per watt and give you 50,000 hr interval between group replacement using RE80 Premium T8 lamps (that costs about $6 a lamp rather than $2-3..). You'll get about 4,000 lumens from a two lamp high efficiency fixture running 25W lamps. 
CREE 40-44W input, 4000 lumen initial, 50,000 hour (supposedly L90 rated) fixture is about $200. They also have a 135 initial (121 mean) lumens per watt model, which should save you 30% in power use over the best T8, but you'd be looking at $400/ea. 

at 13c/hour and power reduction of 13.5W(45W input 25Wx2 super T8 vs 31.5W LED), you'll never pay off the additional cost of $325/fixture. it takes 185K hours. 

LEDs are often given the credit they don't deserve and many of case studies and feedbacks are based on observations before the lamps even hit the first 1,000 hours. Before and after photos are completely useless for comparing performance. The camera automatically compensates the aperture and shutter speed so that it gets a good exposure either way. :laughing:


----------



## Southeast Power (Jan 18, 2009)

Says the fluorescent lamp salesman.


----------



## cuba_pete (Dec 8, 2011)

*hmm...*



Electric_Light said:


> Off the chart flicker contents is a new problem brought on by Light Emitting Decorations. It's not included in product specs since there's no mandate on meeting a certain value.


I was in my basement wrapping presents last night. I hadn't spent much time there since putting in a new el cheapo (Costco) LED fixture. It was then that that I noticed the flicker, and then the sags that would even cause blinking of the light. I went cheap, and now see the cost.

===================

This is an interesting topic which I didn't know existed.

I put your link here: LED's Magazine

Here is another good article from Architectural Lighting.

The IEEE report

I think we'll all be seeing more of this as time goes on.


----------



## ecelectric (Mar 27, 2009)

Here's the ones I use


----------



## Electric_Light (Apr 6, 2010)

cuba_pete said:


> I was in my basement wrapping presents last night. I hadn't spent much time there since putting in a new el cheapo (Costco) LED fixture. It was then that that I noticed the flicker, and then the sags that would even cause blinking of the light. I went cheap, and now see the cost.


It's a huge headache that goes with using Decorations that Emit Light. If it's not part of official specifications, they have no obligations to match it. So, even if you obtain a product sample and you find the flicker content satisfactory, the next production lot may have been revised for production cost reduction and contain a lot of flicker while still meeting the required specs. This is why it's imperative to put flicker index/percent flicker as line items into purchasing specifications. 

"flicker index shall not exceed 0.02 and flicker percent shall not exceed 10%" puts the responsibility on the supplier. LED vendors absolutely hate when you add those stipulations.


----------



## Electric_Light (Apr 6, 2010)

ecelectric said:


> View attachment 41986
> 
> Here's the ones I use


















The Maxlite LED would be the sky blue dotted line. The T8 data is based on measured results. LED one beyond 6,000 hrs is extrapolated. 

Or you can get 2,300 *maintained* lumen per lamp (2380 initial) at 24W/lamp including the ballast using 68,000 hr (48,000hr B10) 28W Super T8 and a NEMA Premium ballast. (figures for 2 lamp ballast) 

If you estimate the mean lumen, that LED is about 1,950 lm/22W and continue to drop more down to 1,610 lm/22W 50,000 hrs while the T8 still holds about 2,200 at the same usage.

Going by mean lumen, you can drop the T8 to 25W lamp and get the mean to 2140 lm per lamp and drop the system power to 22.5W/lamp. At that point, LED saving is squashed to zilch even if you're looking at just the watts. 44W vs 45W for a two lamp fixture. 

Initial to initial, you have 99.1 Lm/W for T8 system vs 104.5 Lm/W. T8 plateaus out on degradation rate, but LED is a steady downhill. 

At such a small difference, LED will not even pay back on incremental cost of LED over the super T8. 

Near the bottom 15 year old T8 systems maintain 75LPW while the best current T8 system maintain 95 LPM reducing the power use about 20%. Selecting the Super T8 at the time the system is due for replacement pays its only the incremental cost of materials, but it will never pay off to tear out the existing system that do not need to be torn out just to retrofit to a higher efficiency system.

If you're going from a magnetic ballast T12, even LEDs will get paid off, but when you compare the retrofit option from mag T12 to super T8 vs LED, the PBP is MUCH longer with LED. 

Diminishing return principle a work  

Find a 9mpg old full size sedan, set gas price at $5 and drive 15,000 miles per year and even an 18 mpg brand new Jaguar will have an eventual payback period.

For linear lamp applications, you can't afford LEDs without a socialist government that will pay for a good chunk of it. The portion that's subtracted from the cost wasn't erased. It was paid by tax money using other people's money.


----------



## Lighting Retro (Aug 1, 2009)

Great documentation Electric_Light


----------



## daks (Jan 16, 2013)

Drivers on a lot of the cheaper led lights won't make 50k hrs. Some may only last a few months. 
Enemy of led systems is heat, if they can't dissipate heat effectively their lifespan goes down the toilet, i.e. 65 deg C is the maximum most led's are supposed to run at (over max for most). From my experience Meanwell makes the best drivers. Cree are the best led manufacturer and Bridgelux makes the best economy led's (chinese led oem). 

A lot of these products were designed and manufactured so fast there is really crap reliability testing on these. Led tubes to replace florescent lights, great idea, no ventilation for all that heat to escape... gets hot, they sag... ooops, whats going to happen 1-2 years from now? Driver failures, solder failures, diodes tuned to friodes Someone mentioned above that someone was marketing glass ones now, still does not address heat dissipation.

Oh, gotta throw in a chart 









No way will I warranty labor with led lights! I see claims of 20-50K hr lifespans,,, but only 1-3 year warranties. :blink: So what did you save when your $60 led lasts 2years? 

There is some interesting info starting to come out with concerns with the light spectrum that these are putting out.


----------



## icdubois (Nov 16, 2013)

Just got done doing a pretty big retrofit for a cabinet maker. Did all their lights, offices, showroom, shop and paint/stain booth. The customer had bought the kits from titan led. They seams to be a pretty easy retro. They were external driver that would have taken the place of the ballast. Just cut all leads on the tombstones as they aren't needed anymore. Half of what we did was 8ft fixtures. These were more of a pain as they were all in the top of the purlins in the roof, the driver needed to be be as close to center as possible due to the length of the leads they had provided. On most of the 8fters power came in on the side so we had to make jumpers to get the driver to the center of the fixture. We also had to drill holes in the covers and put in grommets to allow the leads to pass though with out getting cut. They did however provided clips that would go in the middle of the fixture to keep the tubes from sagging. The troffers that we did went much easier. Drop the lid remove old ballast wire in driver attach leads to both ends and close the cover. We used ideal push in connectors as much as possible and the job went a ton smoother and easier using those. But the ones that were the biggest PITA were the ones in the stain/paint booth. As they fixtures were explosion proof so that added a little more difficulty in trying to figure out where to stick the driver and still be able to get the whole thing sealed up again. But then came the ones on top of the booth. There was only about 13" of clearance to work in. The lids wouldn't stay open and couldn't be taken off. Had to install 2, 3 lamp drivers to get all four lights to work. Then come to find out that we had to remove the tombstone and turn them in the fixture as they were two pin lights but the orientation of the stock pins was in the wrong position. This required prefabing both ends to accept the tombstone in the right position. So doing all that in a space on 13" or less. PITA!!!!!


----------



## icdubois (Nov 16, 2013)

Here's the site for the manufacturer of the lights that we put up
http://www.titanled.net/


----------



## John Peters (Jan 1, 2009)

*Five ways to do a 48 inch LED Tube Retrofit*

It has been almost 2 years now since I originally wrote this article and I have changed my opinion in some areas.

(1) BALLAST COMPATIBLE tubes are INEFFICIENT - They are plug & play but the 18W LED tube uses 22W if you're still using the ballast and of course someday the ballast will fail and require rewiring.

(2) TWIN-PIN BUILT IN DRIVERS - I like these. I cut wires from the ballast but leave it there to avoid disposal fees. I wire it with the black wire to one tomb-stone (both or either pins) on one end of the fixture and the white wire goes to the other end. You do not have to be careful of shorting out the circuit if there are shunted lamp holders. (The two pins are internally shorted together.)

I use “Direct Replacement LED Tubes" Model E2T8D-48-18W-BIXX by www.e2lighting.us I see the company web page but a Google search does not find anyone selling them online! I buy them at Universal Electric San Francisco where they sell only US approved materials. The price dropped down to $21.92 each in April 2016.

(3) BI-PIN BUILT IN DRIVERS - I DON'T like these. You rewire it so there's 110 V going to the two pins on one end of the fixture. DANGER -You have to be careful that you replace or change out any tombstones that are shunted which means that two pins are shorted together 

(4) REMOTE DRIVERS The ones I tried only drives one tube so if you have a 4 tube fixture there is not enough space. I also had some failures with these drivers.
--------

I am glad to see the responses from others that have more experience with the quality of light and life-span that I do


----------



## cuba_pete (Dec 8, 2011)

*Caveat Emptor*

I did not remember this thread until it showed up in my User CP.

My experiences with hybrid and non-hybrid tubes has varied quite a bit over the past year.

No matter which tube design or manufacturer someone decides to go with, I highly recommend that they do a bit of research on the design and manufacture as far as FCC and UL (possiblly DLC too).

My agency is well into $40,000 for tubes that turned out to be inherently unsafe/assembly challenged, and no apparent FCC or UL certification _despite being_ _labeled as such_ in several design instances.

Our contracting officer apparently doesn't believe in any maxims about lowest bidders.

They are energy efficient to a T, but time will tell as far as design life and quality of light over that time span.


----------



## billyhunter (Mar 31, 2016)

The mainstream is the by pass ballast and replace it with non shunted socket with built in driver led tubes. The following link is for reference only.

Unshunted T8 Socket for By-Pass Ballast, Built-In Driver LED Tubes

http://www.bulbspro.com/etlin-fl011...ulder-tall-profile-turn-type-lampholders.html


The Built-in LED T8 Tubes like this

http://www.bulbspro.com/ch-lighting-ch1152-48-18w-850-3.html


----------



## JoeAPinkley (Apr 3, 2016)

Really Informative post and it will helpful for beginners.


----------



## John Peters (Jan 1, 2009)

Excellent advice although I believe that double-ended tubes are safer and you don't have to worry about shunted sockets.

One future problem for the client will be will be to find the same type of tubes 5 or 10 years down the road.


----------



## BigVolt (Oct 24, 2015)

*This one works with or without a ballast, single or double-ended.*

http://www.jameslighting.com/led-magic-tube/


----------

