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Fluorescent Lighting Comparison & Maximising Your Lumens

apollonio

Member
Thanks for the info ScrubNinja! You made me change my mind about my setup, i'll use the CFL bulbs horizontaly now. :)

I'm planning on adding a glass to shield the heat from the plants, i'm aware that this will make me lose a few lumens, is that correct? Wich kind of glass should i use to minimize the light intesity loss?

Be good!
 

ScrubNinja

Grow like nobody is watching
Veteran
No worries buddy. You will lose some light - I believe Pico tested it as 3 point something percent - he didn't mention what kind of glass but I'd assume that is fairly thin glass specifically for reflector use. I was planning to add a heat shield at one stage and I had some glass lined up that's about 3mm thick, but I never used it - but it was from a picture frame. Might be a good idea to use tempered glass if you think there's any danger of it breaking or you're clumsy etc. Just some thoughts and maybe someone can chime in if they know more about it. Best of luck.
 

apollonio

Member
Thanks for the response! I did a research yesterday and couldn't find much about wich glass i should use. I'll try normal window glass 3mm thick, it should be ok since it's only fluoro lights (was afraid it could melt or something). If i find out more about the subject i'll post the info here. :yes:
 

SupraSPL

Member
Good info ScrubNinja, thanks for posting. I;m sure I will be referring back to this thread alot when I am trying to make comparisons for temperature.

One thing I have been trying to sort out, the lumens per watt on the everyday CFLS like the 26 watters. I have tested the bulbs on the Kill-A-Watt and once they warm up, they draw exactly what they are rated to draw. That means they are being treated slightly unfairly when comparing lumens/watt versus the remote ballast types because we don't consider ballast losses. If we assume 15% ballast losses, a 26 watt CFL actually dissipates 22 watts in the tube. The GE 26w 2700k advertises 1750 initial lumens. If that measurement is accurate, then we can say 80 lumens per watt, which is much more than I have ever given them credit for lol.

23w 2700k from Lowes claims 1600 lumens, 81 lm/w.

10w GE 6500k claims 490 lumens, 58 lm/w.
 

ScrubNinja

Grow like nobody is watching
Veteran
I have tested the bulbs on the Kill-A-Watt and once they warm up, they draw exactly what they are rated to draw. That means they are being treated slightly unfairly when comparing lumens/watt versus the remote ballast types because we don't consider ballast losses.

Hi Supra and thanks :) I'm baked and this is getting out of my comfort zone, lol. But I think the root of your issue is that the kill-a-watt is what's not factoring in losses and confusing your figures. You are seeing the figure which isn't taking the power factor into account. It should list the power factor (pf) somewhere, and once that's taken into account, you will have the real indication of power coming into your cab/cfl which goes to making heat, and putting out that retina burning CFL light. There are other reasons why kill-a-watts can be misleading, not sure if all that applies to CFLs specifically but just making a point that they have issues. I'm hoping you understand the concept of power factor or you may get a bit lost but I'll explain as best I can.

So

The GE 26w 2700k advertises 1750 initial lumens. If that measurement is accurate, then we can say 80 lumens per watt, which is much more than I have ever given them credit for lol.

On the surface, using what they tell us, it's giving 67.3 lumens per watt. In reality, in terms of thinking of heat, it's considerably worse, depending on how bad the power factor is. Let's say it was a .5 power factor (50% efficient) - it would be using around 26w plus 50% of that again, so around 39w. That works out to 44.8 lumens per watt. Absolutely craptacular, I'm sure you'll agree. In reality the pf is probably not going to be that low, but use the numbers for your bulb. The CFLs I used to use were .6 pf so it's ballpark.

Lets look at a 55w pll. You get 4800 lumens, so that's 87.2 lpw using what they tell us. The big difference is that they usually have a power factor in the high .9's, mine are >.98. So in terms of real heat, it's using around 55w plus 2% of 55w as the power factor loss (1.1w). That comes out as 85.5 lpw.

In other words, pll tends to beat cfl handsomely in terms of the basic figures alone. In terms of the realistic figures, pll smashes them outta the ring.

Some notes: I think some households have conditioners to fix the power factor? Not really sure though. Also, I believe that while you run the cfl via the kill-a-watt, it does have a high power factor, and the figures can be re-adjusted to suit, but at the end of the day, they still lose out.

Does all that make sense? :tiphat:
 

SupraSPL

Member
I'm on board with what you are saying. I wasn't referring to power factor in my earlier posts, only the ballast losses. For those just breezing through, in summary: literature stating compact CFL's efficiency penalizes them by the inclusion of ballast losses whereas tube fluoro's ballast losses are not considered.

The wattage for tube fluoros is based on the wattage that their actual bulbs which ignores ballast losses, whereas compact fluoros wattage is listed based on the bulbs + the ballast which is built in. Therefore tube fluoros get an advantage "on paper" but not in practice.

I just tested a 15 watt GE 18" fluoro with the Kill-A-Watt. It reads exactly 20 watts. It is using a super cheap magnetic ballast. I also tested a 15 watt compact fluoro, it reads exactly 15 watts.

So, if we want to compare a compact CFL lumens per watt with the figures published for tube fluoros, we have to compare apples to apples. We would have to subtract ballast losses from the compact CFLs in order to compare directly to fluoro tubes.

I think this is an acceptable method because almost all lamp types suffer from ballast losses. When it comes down to it, we are trying to compare the bulbs not the ballasts. I'm not saying the ballasts are not important, just that they are a separate consideration. If we want to be as green as possible, we can choose the highest efficiency digital ballasts which can go up better than 90% in some cases.
 

SupraSPL

Member
Re: power factor. Separate from ballast losses, this is another important consideration and is related to the design of the ballast. Digital or electronic ballasts have a near perfect power factor. Magnetic ballasts are typically 50-60% efficient but they can be "corrected" by the addition of a large capacitor (commonly used in bigger HPS ballasts and required by laws in Europe I believe). My old 70w HPS had a pf of .5. The 15 watt fluoro tube I mentioned above using the cheapo magnetic ballast, also .5 (50% efficient) It is dissipating 15 watts in the bulb, 5 watts in the ballast, so overall it is drawing 40VA. You are correct, that is craptacular!

One interesting thing I have noticed regarding compact fluorescents. While it is true that their power factor tends to suck when measured individually, if there are several of them on a line with other fluoros and fans, the pf improves to about .75. I'm not sure if this is because the Kill-A-Watt is confused by the complex mixture of phase angles or if the measurement is accurate overall.
 

ScrubNinja

Grow like nobody is watching
Veteran
Well that is some interesting points man. I had to read your posts many times, and activate my brain, lol. :help: So here are my thoughts and questions and hopefully I understood you right.

For those just breezing through, in summary: literature stating compact CFL's efficiency penalizes them by the inclusion of ballast losses whereas tube fluoro's ballast losses are not considered.

Which literature are you referring to exactly? The tube fluoros have to be run on a ballast to be tested, so I'm not understanding how they don't take ballast loss into consideration?

I understand that an "efficient" tube fluoro is not going to be efficient and match up to expectations if it's run on a non efficient ballast. I think that's where you were headed right?

I just tested a 15 watt GE 18" fluoro with the Kill-A-Watt. It reads exactly 20 watts. It is using a super cheap magnetic ballast.

So use an efficient ballast and any questions of inaccurate ratings are gone, no?

Thanks for taking time to discuss. I'm here to learn as much as anyone else is. :)
 

SupraSPL

Member
Haha I have a hard time wording my ideas. I know some of what I wrote is probably clear as mud but I just write it and hope that the readers can sort it out somehow. That would get even worse if I was smoking. I don't think I road what know this is..

When I say literature I mean the watts listed on product packaging and the bulbs themselves. For example, the 15 watt tube I tested says 15 watts on the actual bulb itself, and that does not include the ballast losses. That is the case with all tube fluoros. Compact CFLs on the other hand say 26 watts right on it and that does include ballast losses. So we are using the wattage and the lumen figures posted on the packaging, even though one includes ballast losses and the other does not. This gives the compact an unfair apparent loss of efficiency when comparing against other bulbs. HPS do not include ballast losses when listing wattage either.

So to even the playing field when comparing bulb efficiency, I suggest assuming 15% losses in the CFL ballast. Therefore a 26 watter should be considered a 22 watter with 1700 lumens.

The losses may be higher. To find that out we need to crack the ballast open and get in there with a multimeter to find out how much the bulb is actually dissipating.

Of course this is just for bulb comparison purposes. All lamps whether LED, HID or fluoro will have ballast losses which I have seen vary from 7%-25%, so still a huge part of total system efficiency.
 

ScrubNinja

Grow like nobody is watching
Veteran
Hmmm okay I get what you're saying, but I think you missed something and I have literature to prove it, lol.

So okay bare with me here for a theoretical exercise. You have been given the job to test a tube fluoro for the manufacturers so they can put the ratings on the bulbs and packaging. To do this you will have to hook it up to a ballast, correct?

This ballast you use, "reference ballast" is the term, will be affected by loss like any other ballast, correct? Sure it will be a good ballast, they're not gonna test it with a cheap one like you used, but it's a ballast more or less like any other, and it has *some* loss/inefficiency.

It has to be hooked up to a ballast and therefore is taking ballast factor into account by default, by my reasoning, which is admittedly shaky at best. But hear me out...page 4-4 of Advanced Lighting Guidelines:

One of the most important ballast parameters for the lighting designer/engineer is the ballast factor. The ballast factor is needed to determine the light output for a particular lamp-ballast system. Ballast factor is a measure of the actual lumen output for a specific lamp- ballast system relative to the rated lumen output measured with a reference ballast under ANSI test conditions (open air at 25 °C [77 °F]). An ANSI ballast for standard 40-watt F40T12 lamps requires a ballast factor of 0.95; the same ballast has a ballast factor of 0.87 for 34-watt energy saving F40T12 lamps. However, many ballasts are available with either high (conforming to the ANSI specifications) or low ballast factors (70% to 75%). It is important to note that the ballast factor value is not simply a characteristic of the ballast, but of the lamp-ballast system.

My copy and paste with PDFs is not working so that was a pain in the ass, but see what I bolded? It seems to say clearly that ballast factor is taken into account when measuring. Indeed it was 0.95 in black and white. The ratings on the bulb/packaging were taken on a ballast with a BF of 0.95. So I am dying to know if I'm crazy, misunderstanding, or you agree with that? lol. Here is what you said, for the record:

(....) compact CFL's efficiency penalizes them by the inclusion of ballast losses whereas tube fluoro's ballast losses are not considered.

If we're agreed that it was in fact considered, and you are still with me - that was published for 1993. Presuming they still use the same guidelines, if I was to buy a ballast that is more efficient than the 0.95 reference ballast, my fluoro tube would be performing better than it says on the packaging. I'd be using a ballast that was more efficient than the reference ballast used to measure performance.

If I used a shitty ballast, I'd get shitty performance, which is what you see hooked up to your (no offense, I have some too) shitty ballast.

I hope this makes sense or otherwise helps me to understand what I'm missing, and hopefully explains why you can't be jiggling the figures for one style of light, as they were both tested & rated with ballasts. Peace. :tiphat:

PS: Just in case it's not clear, I do agree that ballast factor should be taken into account to compare CFLs and tube fluoros accurately, if you're using a sub-ansi standard low efficiency ballast for your tubes. But for that, I have another exercise:

You go to the store to buy a new ballast for your brand new fluoro tube growroom. On the shelf is a low efficiency ballast, and a high efficiency ballast. Which one do you buy? :)
 

SupraSPL

Member
Hi SN, I'm glad you bring these points up because they are understandable arguments. Ballast factor is a separate measurement from bulb wattage or lumen output. It is used to evaluate ballast+bulbs together, whereas bulbs specs are measured and listed separately from the ballast. You would never see a ballast factor printed on the packaging for a fluoro tube. Yes it is true that ballasts can be used when manufacturers test the bulbs, but they still list the actual bulb dissipation figure on the bulb's packaging and disregard the ballast losses (which is understandable and preferable).

On a personal note I would just like to point out I do not like Advance's use of ballast factor. It seems like a confusing and useless calculation that has no place on a ballast spec sheet. I suspect it may be a way of hiding the efficiency of a particular ballast? When I searched the non-copyable PDF from Advance to seek out the typical efficiency of the optanium ballasts, there was none listed. There was only a vague mention of ballast factor which ranged from .75- 1.25 lol. Meanwell on the other hand lists the ballast efficiency under various loads and that is some useful data so thanks to Meanwell.

Imagine you are at Lowes buying a T8 tube and it says 32 watts on the bulb. You grab an advance electronic ballast in the store and fire it all up. Run it through the Kill-A-Watt and it will read approx 37 watts. (I arbitrarily gave them 85% efficiency)

Next grab a CFL off of the shelf that says 26 watts. Hook it up to Kill-A-Watt and it will read 26 watts once it warms up and stabilizes.

Since both bulbs had a lumen figure printed on their packaging, that is how this discrepancy arises when we try to calculate lumens/watt for efficiency comparisons. It's only a slight consideration for CFLs, but we might as well be thorough and fair.

As a side note, I chose the crappy magnetic ballast (75% efficient and lowly .5pf) only because it was easy to reach, but significant losses would result regardless of the ballast used.

Sorry you had to type that paragraph. Your copy paste is probably OK, I'd bet that PDF was blocking you somehow. I had that happen to me recently and I suck at typing lol.
 
I think what SupraSPL is trying to say is that the fluro tubes are rated as just the tubes energy use as the manufacturer has no idea what ballast you will use with it so to save confusion they state just the tubes energy use instead of a list of possible tube + ballast uses that would cover all possible ballast types and efficiencies.

Whereas CFL's have the ballast built in so the manufacturer knows what ballast it has and therefore how much energy in total it will use.

I agree to get a proper comparison the tube plus ballast energy use should be used when calculating the lumens per watt rating.
 

ScrubNinja

Grow like nobody is watching
Veteran
Thanks mess'n. :yes: I learnt a bit too, lol.

Can you guys find any reference about the cfl thing supra mentioned? I figure it should be noted in the ALG or on a webpage somewhere - I haven't come across anything.
 

SupraSPL

Member
I don't see much discussion about that topic either. Page 2 of this document mentions it:

"Remember to account for ballast losses; compact fluorescent ballasts usually draw 3 or 4 watts. For bulb-and globe-shaped
lamps, most manufacturers include the ballast losses in the stated wattage."
 

fatigues

Active member
Veteran
Nice post Scrub.

The overall result is what we've been saying here for a loooong time: 55w PL-L lights are the bomb for microgrows.

The greatest downside with PL-L lamps is that they are not readily accessible at retail in most areas. Point is: they are available online and that's the best place to get them - no matter where you are.

Some people have this great NEED to rush off to Home Depot or Wal-Mart and grab some stuff and "make do". Will that work? Well - to a point, yes it will. But you are much better just ordering the stuff online and waiting a week.

CFL's and T5s /T5HOs aren't as efficient PL-L lights and neither format will grow as much weed in the same space for the same wattage as a PL-L setup. PL-L gives nice tight nugs with significant yields for a personal grow.

While there are a number of reasons to prefer a CMH or an HPS lamp, for a personal grow, especially in a tight area, PL-L lights are the preferred choice, hands down.

And yes, using 440w PL-L, you can harvest half an elbow off of one plant. Try getting that with CFLs or T5s.
 

medicaluser2

New member
Hey Scrub,

Ive read a lot of your posts, thanks for the great info. Who manufacturers the CFLs you use? What model ? Can you tell any difference between them and heat production?
 

blinded

New member
Hello guys , good day :)
i was wondering if i could use CFL ballasts to power Fluorescent tubes?
can i match the wattage by multiplying the ballast (not sure if it work but i'd like to be optimistic :)
most times the ballasts of broken CFLs are functional and would be a waste to throw 'em away - not to mention it will be a cheap alternative for electronic ballasts-.

Cheers
 

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