Watts lost through ballast?

[MNSparky]

We do maintenance work for a large indoor mini-storage facility and I'm trying to sell them on an LED retrofit of their 800 4' T8 lamps. I'm looking to use 18w line voltage LED lamps so I can take the ballast out of play. I'd like to be able to give them an estimated % of energy saved as part of the quote. I can do the math on the lamps themselves, but does anyone know approx how many watts are lost through a ballast? The ballasts are around 15 yrs old I'm guessing. There are 200 of them so I'm guessing what ever it is will add up to significant savings.

Also, does anyone know how the retrofit would effect the electric bill as far as a change in inductive reactance? I'm not sure if the LED drivers would cause the same, more, or less inductive reactance on the system. I don't deal with power factors a lot so I'm trying to remember what I can on the subject... Thank you for your thoughts!

 

[peter d]

Any ballast spec sheet should give you this info, they do for HID ballasts.

As for power factor, I'd say you can safely ignore that issue.

 

[kwired]

Power factor you do have is harmonic distortion power factor and is not the same thing as inductive reactance power factor. Older magnetic ballasts had inductive reactance. Electronic ballasts could have some inductive reactance as a result of having any kind of transformer in them - but would be very low in comparison to what a magnetic ballast has, such transformers in an electronic ballast are likely for controls on the board and not transforming main power to the driven lamps.

 

[tom baker]

The T-8 linear luminaires are very efficient and it may not be cost effective to go with LED. What type of T-8s, 32 watt, 34 watt? Does your POCO have a rebate program for lighting retrofits?
How often do the T-8 ballasts fail- what about lamps?

 

[kwired]

The T-8 linear luminaires are very efficient and it may not be cost effective to go with LED. What type of T-8s, 32 watt, 34 watt? Does your POCO have a rebate program for lighting retrofits?
How often do the T-8 ballasts fail- what about lamps?

Also take into consideration how many hours a day these lights run. If they are on a lot, there could be a reasonable payback in energy savings, if they are not on all that much you may never recover the installation cost in energy savings costs - within a reasonable time anyway.

 

[JFletcher]

The energy savings on bypassing the ballasts will be small compared to the maintenance savings of never having to replace them again.

Does your facility have occupancy censors?

 

[Fulthrotl]

We do maintenance work for a large indoor mini-storage facility and I'm trying to sell them on an LED retrofit of their 800 4' T8 lamps. I'm looking to use 18w line voltage LED lamps so I can take the ballast out of play. I'd like to be able to give them an estimated % of energy saved as part of the quote. I can do the math on the lamps themselves, but does anyone know approx how many watts are lost through a ballast? The ballasts are around 15 yrs old I'm guessing. There are 200 of them so I'm guessing what ever it is will add up to significant savings.

Also, does anyone know how the retrofit would effect the electric bill as far as a change in inductive reactance? I'm not sure if the LED drivers would cause the same, more, or less inductive reactance on the system. I don't deal with power factors a lot so I'm trying to remember what I can on the subject... Thank you for your thoughts!

led's measured in the wild can have significant variances in power factor.
i've seen them at 98%, and at 88%. that's real world, measured with a meter.
a lot has to do with dimming controls and some of them tweak things pretty well.

the retrofit ones vary quite a bit in quality, as opposed to mainstream luminaries
where the entire fixture is replaced. longevity is also an issue.

occupancy sensors would be well worth the cost to include in this. that will do a
lot for saving money. turning the lights off is the most bang for your buck.

i've done four certifications on self storage, and they all have 4' led industrial fixtures,
along with an occupancy sensor on each fixture. lights stay on for 5 minutes at full
brightness, dim to 50% for 5 minutes, and go off.

that will also extend the life of the led's. they don't last forever.

also, consider putting a surge supressor on the service. a bad voltage spike on
a building full of led fixtures, can ruin your whole day.

 

[MNSparky]

The existing lamps are 32w T8's. The walk aisles are all controlled by occ sensors while the single main drive-in aisle have the fixtures on 24-7-365. There are maybe 20 fixtures that cover that aisle.

We are starting to go there a lot more frequently that we have in the past for ballasts and lamps, which makes me think the originals are nearing the end of their life. This is what spurred the conversation with the district manager about LEDs. We probably go about once a month now to change out 2-3 ballasts and several lamps.

 

[Saturn_Europa]

The existing lamps are 32w T8's. The walk aisles are all controlled by occ sensors while the single main drive-in aisle have the fixtures on 24-7-365. There are maybe 20 fixtures that cover that aisle.

We are starting to go there a lot more frequently that we have in the past for ballasts and lamps, which makes me think the originals are nearing the end of their life. This is what spurred the conversation with the district manager about LEDs. We probably go about once a month now to change out 2-3 ballasts and several lamps.

Spot changing bad bulbs and ballasts is pretty inefficient. I have also heard that burned out fluorescent bulbs can kill a ballast. Many larger facilities have re lamping entire buildings on a fixed schedule. Maybe just sell them on changing out all the bulbs at once.

 

[MNSparky]

Spot changing bad bulbs and ballasts is pretty inefficient. I have also heard that burned out fluorescent bulbs can kill a ballast. Many larger facilities have re lamping entire buildings on a fixed schedule. Maybe just sell them on changing out all the bulbs at once.

That's what I'm trying to do with the LED lamps. I don't see the point in relamping the facility with flourescents on old ballasts because we will still end up going back to replace ballasts as they die off. They'd pay almost the same labor cost to do the work as the LED project, but the LED project comes with the benefits of lower energy use, no more ballasts and a rebate from the PoCo.

From what I can find online, ballast losses aren't as great as I thought they would be. It looks like it would be somewhere around 10-20 watts per ballast, depending on which ballast we are talking about. Take the middle of the road at 15w x 200 = 3000w. Not a huge deal.

 

[MNSparky]

also, consider putting a surge supressor on the service. a bad voltage spike on
a building full of led fixtures, can ruin your whole day.

Not a bad idea. It seems like this would be a good idea for new buildings that are mainly LED, is this becoming a standard practice? I haven't noticed any increased use of them, but we don't do a lot of brand new builds.

 

[Electric-Light]

We do maintenance work for a large indoor mini-storage facility and I'm trying to sell them on an LED retrofit of their 800 4' T8 lamps. I'm looking to use 18w line voltage LED lamps so I can take the ballast out of play. I'd like to be able to give them an estimated % of energy saved as part of the quote. I can do the math on the lamps themselves, but does anyone know approx how many watts are lost through a ballast? The ballasts are around 15 yrs old I'm guessing. There are 200 of them so I'm guessing what ever it is will add up to significant savings.

Also, does anyone know how the retrofit would effect the electric bill as far as a change in inductive reactance? I'm not sure if the LED drivers would cause the same, more, or less inductive reactance on the system. I don't deal with power factors a lot so I'm trying to remember what I can on the subject... Thank you for your thoughts!

Not one bit. Fluorescent fixtures intended for commercial use are power factor corrected and yields well in excess of 0.90. ESCOs love type Bs, because it creates demand for service. Some of the hype around ballast bypass is sales pitch as justification for installation labor. It doesn't quite work that way. HIDs, fluorescent lamps all require a ballast to operate. The most primitive ballast is resistance. There used to be a self ballasted mercury vapor lamp with an incandescent lamp built into the bub which acted as a ballast. This is also the type of ballast used for very low power LEDs as well as LED strip lights which generally have three LEDs and a resistor per "rung"and the entire rope is constructed like a ladder.

Electronic fluorescent and LED ballasts are built almost the same. They're based on the switch mode power converter technology that is used for modern power adapters and computer power supplies. They can be located as a unit with the lamp or exist as a separate unit. For example, 13W screw-in with integral disposable ballast do not waive the ballast loss compared to a 13W 4-pin external CFL system despite the ballast being transparent to the user. Ballasts have a limited lifespan, especially the electrolytic capacitors used in them regardless of what it is intended to operate.

Philips have "drop-in" lamps optimized LED ballast so it can also be considered type C (for use with external driver), but it's really just a ballast optimized for maximum efficiency at the power level of these lamps rather than F32T8. Some, such as GE offers type A/B that uses the internal ballast when wired one way. When wired like a normal fluorescent lamp, internal ballast is bypassed and T8 fluorescent ballast drives the lamp. I don't like type B's, because the wiring line voltage to tomb stones isn't standardized and there are safety and compatibility issues with it. The advantages of type A/B lamps are they can be dropped-in, then the fixture can be rewired for type B and the integral ballast would take over.

Ballast efficiency is watts delivered to lamp over watts taken from the power source. This can be between 70 to 95% depending on many factors. It's often not published as final product specs, because, ballasts are usually not rated this way. Much like your car's specs do not come with the gallons per hp-hour of the engine. Generally, NEMA premium T8 ballasts are in 90-95% range when driving rated quantities of 32W lamps.

http://www.gelighting.com/LightingW...g-Refit-Solutions-Whitepaper_tcm201-69385.pdf

Pay close attention to the life rating on recent value lamps. The life rating can be much worse than comparably priced premium T8. The premium version LED with better durability cost significantly more.
http://forums.mikeholt.com/showthread.php?t=179665

 

[dkidd]

It looks like it would be somewhere around 10-20 watts per ballast, depending on which ballast we are talking about. QUOTE]

That figure is way too high. And the actual input watts depends on the specific lamp-ballast combination. A 32 watt lamp could use more or less than 32 watts depending on the Ballast Factor for that lamp-ballast combination.

 

[kwired]

It looks like it would be somewhere around 10-20 watts per ballast, depending on which ballast we are talking about. QUOTE]

That figure is way too high. And the actual input watts depends on the specific lamp-ballast combination. A 32 watt lamp could use more or less than 32 watts depending on the Ballast Factor for that lamp-ballast combination.

I was thinking that seemed pretty high as well. 10 watts total loss for a 4 lamp ballast, maybe but still probably on the high side of reality.

 

[Electric-Light]

It looks like it would be somewhere around 10-20 watts per ballast, depending on which ballast we are talking about. QUOTE]

That figure is way too high. And the actual input watts depends on the specific lamp-ballast combination. A 32 watt lamp could use more or less than 32 watts depending on the Ballast Factor for that lamp-ballast combination.

Practically all T8 lamps in use operate on electronic ballasts and overwhelming majority are 0.88 BF. It may surprise you, but this means most T8 ballasts in the field are designed to put out 88% output with electrical power delivered to the lamp in the ballpark of 25W per 4' 32W lamp. (There's a gain factor of 10-12% in lumens per watt when you drive fluorescent lamps at high frequency *see note 1). Just about every other commercial & industrial ballast for non T8 lamps operate at 95-100% of rated output. I'd just chalk it off as traditions.

Obscure magnetic ballasts to run 32W T8 lamps exist, but they're very uncommon. This is where sales people come up with the 72W per pair figure.

15 year old two lamp T8 ballasts has a line input of around 58-59W or ~85%.
Premium efficiency ballast available today offers you the same for 54-55W, which puts the output-to-input efficiency around 92%.
Probably the more significant savings is that 120-277v ballasts are auto regulating and do not let line voltage variations sway power consumption. 4 lamp version is a hair better knocking off another half a watt input per lamp.

Many ballasts can run 2 and 3 foot lamps, as well as run one lesser lamp than maximum but they're tuned for optimal efficiency running maximum quantity of 32W 4' lamps. so the efficiency suffers in other combination and many older single voltage ballasts are often incompatible with 25W 4' T8 or LED drop-ins.


This here is how its looking for the most current Philips LED linear lamp paired with their ICN-2P16-TLED-N dedicated LED ballast which offers performance very very close to operating on ICN-2P32-N ballast for fluorescent lamps which maintains backward compatibility with FL lamps. The boxed one is their premium DLC 4.0 version. There's Home Depot/builder's grade glass envelope LED lamp that puts out 2,100 day-one lumens per lamp but has significantly worse long term durability that is trumped by premium T8 lamps at lower cost per lamp. You'll see that LED lamps only compete against 25 and 28W saver lamps, which are only usable in temperatures not colder than room temp. 32W lamps that can operate at lower temp puts out correspondingly more light. I crossed out the 700 series lamp, which is the lowest bid lamp. Premium LED lamps cost far more than premium T8 lamps, so I believe its fair to leave out the cheapest FL lamp.


Philips TLED with dedicated Philips LED ballast. Not much difference if using their NEMA PREM T8 ballast. The lumens in this chart is per lamp, watt is per two lamp system. As far as these lamps are concerned, these lumens assume operation on dedicated LED ballast or 0.88 BF FL ballast. LEDs and fluorescent both require a ballast regardless of how sales department chose to disclose it and with fluorescent ballasts hitting 90-95% efficiency, we're already very close to realistic limits. Line voltage LED lamps just move the ballast loss to inside the lamp envelope. There are four pins per lamp and at present time, pin assignment is all over the map on "ballast bypass" type lamps meaning that replacement lamp bought to replace failed LED lamps could require rewiring to accommodate them.

This is what it's looking like with contemporary fluorescent system. Lumens and watts are both in pairs. The outputs for both technologies are day-one performance, but those builder's grade LED lamps that you can buy for under ten bucks have steeper LED degradation slope than F40CW.

*note 1:
When you crunch numbers with book values, you can actually end up with higher lumens per watt than dividing the lumens by watts from the lamp's box. This is because lumens per lamp watt is calibrated at 60Hz for T8 and T12 lamps. All fluorescent lamps make a tad over 10% more light per watt on high frequency. Even though T8 lamps can operate at 60 Hz or high freq, almost all T8 lamps in the field are operated at tens of KHz. T5 lamps are not intended to be operated at 60Hz and as such the specs for T5 lamps are measured at 25,000 Hz which means you divide out the lumens by watts on the box, but this has been exploited by sales people to present T5 as having superior efficiency.

I was thinking that seemed pretty high as well. 10 watts total loss for a 4 lamp ballast, maybe but still probably on the high side of reality.

 

[Barbqranch]

We replaced around 750 fluorescent tubes w/ Philips LEDs, the type that still use the electronic ballasts in the fixture. POCO paid for much of the cost. Everyone loves the color, and they are all the same color, instead of the higgledy piggledy colors we had before. For our plant, color rendition is important.

Just a little over a year, no failures.

Only problem install them, some of the fixtures only had one connection per tombstone, and it seemed like they were always wrong so the other one needed connecting. Not a big deal.

 

[Electric-Light]

We replaced around 750 fluorescent tubes w/ Philips LEDs, the type that still use the electronic ballasts in the fixture. POCO paid for much of the cost. Everyone loves the color, and they are all the same color, instead of the higgledy piggledy colors we had before. For our plant, color rendition is important.

Just a little over a year, no failures.

Only problem install them, some of the fixtures only had one connection per tombstone, and it seemed like they were always wrong so the other one needed connecting. Not a big deal.

Tombstones with two holes do not require two connections as it's internal to the socket. If there are four holes and they were missing the jumper, your T8 lamps were getting substantially lower life than they should.

I see you didn't mention the specific Philips model. The lamps you're talking about is from the InstantFit line, but there's a big catch. They have multiple types beyond the color. Go to "product bulletin". The models not noted with a black or a blue dot on the left aren't DLC qualified.

Only some of their offerings have specs surpassing gas-in-tube premium T8. Those cost $30 a piece.

Suppose you were in the market for tires. Perhaps you'd want to know more than they're BF Goodrich brand, estimated life in miles before they're worn to the legal limit and people's opinion about how they like them with experience of under 3,000 miles. Great, so they're supposed to last 60,000 miles? Perhaps you may want to know the exact model, how traction, ride quality and noise degrade after 30,000 miles.

Platt Electric lists the cheap, reduced performance model as the top seller. This model is not DLC qualified and they don't live up to the performance of premium T8. Not even close when it comes to long term durability. It is also made of shatterable glass(not coated with barrier film). It's great for residential use where full output instantly is greatly appreciated and frequently subject to on cycle lasting only a few minutes.

This one has impressive performance, but the price is high.

 

[iwire]

Tombstones with two holes do not require two connections as it's internal to the socket. If there are four holes and they were missing the jumper, your T8 lamps were getting substantially lower life than they should.

I see you didn't mention the specific Philips model. The lamps you're talking about is from the InstantFit line, but there's a big catch. They have multiple types beyond the color. Go to "product bulletin". The models not noted with a black or a blue dot on the left aren't DLC qualified.

Only some of their offerings have specs surpassing gas-in-tube premium T8. Those cost $30 a piece.

Suppose you were in the market for tires. Perhaps you'd want to know more than they're BF Goodrich brand, estimated life in miles before they're worn to the legal limit and people's opinion about how they like them with experience of under 3,000 miles. Great, so they're supposed to last 60,000 miles? Perhaps you may want to know the exact model, how traction, ride quality and noise degrade after 30,000 miles.

Platt Electric lists the cheap, reduced performance model as the top seller. This model is not DLC qualified and they don't live up to the performance of premium T8. Not even close when it comes to long term durability. It is also made of shatterable glass(not coated with barrier film). It's great for residential use where full output instantly is greatly appreciated and frequently subject to on cycle lasting only a few minutes.

This one has impressive performance, but the price is high.

I guess you missed the part where they said they were happy with the results.

 

[Electric-Light]

I guess you missed the part where they said they were happy with the results.

I'm aware. He's happy so far which is only as far fraction of anticipated life. Long life is one of the main key performance and this includes performance stability over the expected lifespan. Just over one year is only a small fraction of expected life for TLED lamps and doesn't tell much about longevity.
He wasn't specific enough for me to comment on:
"everyone loves the color, and they are all the same color, instead of the higgledy piggledy colors we had before. For our plant, color rendition is important."

He could have meant having lamps of all the same kelvin temp instead of prior conditions caused by perpetually chasing after failed lamps with the cheapest "four foot long T8 fluorescent light bulb". I also am unsure of his context of importance behind color rendition. The idea of good rendition in industrial environment is very different from retail. Printing industry wants to have viewing conditions very close to ANSI or ISO conditions for improve consistency. Other industries may see good rendition as something that make defective conditions pop out to improve quality control. So his comments might be more generic and have little to do with merits of the specific product. The choice of one of half a dozen or so kelvin temps have immediately noticeable effect on perceived color rendition. Communication may have created psychological attribution to LED technology or the product.

 

[mivey]

I'm aware. He's happy so far which is only as far fraction of anticipated life. Long life is one of the main key performance and this includes performance stability over the expected lifespan. Just over one year is only a small fraction of expected life for TLED lamps and doesn't tell much about longevity.
He wasn't specific enough for me to comment on:
"everyone loves the color, and they are all the same color, instead of the higgledy piggledy colors we had before. For our plant, color rendition is important."

He could have meant having lamps of all the same kelvin temp instead of prior conditions caused by perpetually chasing after failed lamps with the cheapest "four foot long T8 fluorescent light bulb". I also am unsure of his context of importance behind color rendition. The idea of good rendition in industrial environment is very different from retail. Printing industry wants to have viewing conditions very close to ANSI or ISO conditions for improve consistency. Other industries may see good rendition as something that make defective conditions pop out to improve quality control. So his comments might be more generic and have little to do with merits of the specific product. The choice of one of half a dozen or so kelvin temps have immediately noticeable effect on perceived color rendition. Communication may have created psychological attribution to LED technology or the product.

Yep. They could have just as easily "we like the new lights because they are better than the old worn-out, poorly maintained lights".

You make a good point that they could just be happy because it was better than the old, not better than an alternative new. I find many times that industrial decisions are not always vetted thoroughly. Many decisions are made by those that have limited knowledge without input from those in the trenches that know better. It is rare for management to admit a bad call and they will many times push the idea that they made the right call and look for alternate excuses to blame since their heads are on the line. Such is life.

LED sales are full of hype and misinformation, at least in what I have seen. One really should dig into the details but is not often done. I appreciate the info. There are some great LED solutions and some not so great.