"But in the 120V areas, where the ballast has to contain some voltage boosting and with electronic ballasts you just can not be sure at all"

I think it can be assumed that when the ballast is loaded below 32W, nominal F32T8 arc voltage (standard) <= ballast output voltage <= ballast OCV (probably max allowed is defined in some standard too). This allready is a limited voltage range. Run a boost converter up to a known voltage (higher than any expected input voltage) inside the tube, same as with the "90..250V" power supplies with PFC

"But that means the full 32W (for a 32W fixture) power to be delivered to the LED's. And that is about double to what the users want from this retrofit."

If the users want to save half the power, why havent half the power been installed in the 1st place with the Fluorescents ?

"But in the 120V areas, where the ballast has to contain some voltage boosting and with electronic ballasts you just can not be sure at all"

I think it can be assumed that when the ballast is loaded below 32W, nominal F32T8 arc voltage (standard) <= ballast output voltage <= ballast OCV (probably max allowed is defined in some standard too). This allready is a limited voltage range. Run a boost converter up to a known voltage (higher than any expected input voltage) inside the tube, same as with the "90..250V" power supplies with PFC

Around the nominal operating point most ballasts are closer to a constant current source. So increasing the load voltage means increasing the real power delivered. You may decrease the real power by clamping the input voltage lower, but usually you can not go further than about 10% or so. So good for "energy saver" fluorescent tubes, but not enough difference for LED retrofit.

When going to the higher voltages, in order to really reduce the power to half, the thing has to operate near the ballast OCV. But there is a problem: Many ballasts feature everything but ellyptical (a common shape in case of a linear reactance feeding a resistor) load characteristic. The thing is, most ballasts employ nonlinear components. Plus many do employ ignition voltage boost (does not count as OCV, but whatever load is there, it should count with it). So when you make a boost converter or so (anything that may adopt to any input voltage) as the front end, you may easily end up with an unstable operating point when the existing ballast output impedance is too high.
The thing is not only about finding an operating point, but to match the load vs source characteristic so, the desired operating point is possible to maintain.

"But that means the full 32W (for a 32W fixture) power to be delivered to the LED's. And that is about double to what the users want from this retrofit."

If the users want to save half the power, why havent half the power been installed in the 1st place with the Fluorescents ?

That is a question for a million, but don't ask me...
The thing is, with many installations the big part of the light from the fluorescent really gets wasted (consumed by the fixture body parts, like the plain white sheet metal behind the tube absorbing around 50% of the light or so), so the beam angle reduction from the LED's does mean the same lighting work with almost half of the lumens needed.
Yes, you may get the same by replacing the fixtures for ones with more efficient optical control (real mirrored finish instead of the plain white paint) or with decent LED fixture (with proper connections and heat sinking), but these tubes are intended to replace the fluorescents in existing fixtures

Can a front end be made with constant current load characteristic, ove wider range than the ballast, so it "defeat" the ballast's regulation ?

How about clamping the voltage below that of the FL lamp arc voltage ?



The optical efficiency of ordinary White colored Fluorescent strip light is about 80% (79% from the spec sheet of Gaash 5054 : http://www.lighting-gallery.net/gallery/displayimage.php?album=2158&pos=14&pid=108747 )

The LED tube discussed here is non directional, so its light would be subject to the same optical losses as a Fluorescent lamp

The directional LED lamps may get more Lm down, but their glare is higher (double if you count just the surface luminance, way higher if you count the contrast between the bright tube and the dark ceiling behind it), which offsets by far any success in decreasing that 20% losses

And finally, there is the efficacy, at 81 Lm/W for this LED tube (typical figure for other LED tubes i seen too) vs 101 Lm/W for the 36W T8 at 32W on HF

So there still is no gain by using the LED tube

Can a front end be made with constant current load characteristic, ove wider range than the ballast, so it "defeat" the ballast's regulation ?

That means the real power input will depend on the ballast voltage with that current. That may vary more than factor of two.
So again, the power you get would be everything but close to what you really need.
So unlike the LED ballast is so intelligent to first "probe" the characteristic and then based on that set some compatible operating point and mode (and that would need pretty complex processing, with miscalculations being rather common problems), so I dount it will ever work in any reliable way.

How about clamping the voltage below that of the FL lamp arc voltage ?

To go to half of the power, you would need half the voltage or even below (as the ballast current will likely increase - and you do not know how much). But for many ballasts that means quite severe overload of the inner components, so it will most likely kill it.
So not flying either.


Generally: Of course, you may just assume the characteristic of the mostly used ballast models hoping most other ballasts would be similar and design for these, but then sooner or later someone will put it on some other ballast and you have quite nasty failure...

The optical efficiency of ordinary White colored Fluorescent strip light is about 80% (79% from the spec sheet of Gaash 5054 : http://www.lighting-gallery.net/gallery/displayimage.php?album=2158&pos=14&pid=108747 )

The LED tube discussed here is non directional, so its light would be subject to the same optical losses as a Fluorescent lamp

The directional LED lamps may get more Lm down, but their glare is higher (double if you count just the surface luminance, way higher if you count the contrast between the bright tube and the dark ceiling behind it), which offsets by far any success in decreasing that 20% losses

And finally, there is the efficacy, at 81 Lm/W for this LED tube (typical figure for other LED tubes i seen too) vs 101 Lm/W for the 36W T8 at 32W on HF

So there still is no gain by using the LED tube

It depend on the exact fixture. Not all white coats are just absorbing light, nor all "silvery" finishes are really efficiently reflecting it back.
Many times the lacquer just get chemically attacked so it gets brown (but then I would suppose the plastic tube will end up in the same state), many times the reflector is just corroded, many times there is even none at all.
But overall: Indeed, the retrofit tube will never be as efficient as the purpose made LED fixture, as well as it will always be way more expensive than the fluorescent tube. The only advantage I may see is, if some space has changed it's main use and so frequent ON/OFF cycles are to be expected. But even that I would consider as a temporary fix, before the proper fixtures would be installed instead.

For the LED efficacy, 4000K CRI80 LED's are at about 140lm/W when bare (those already sitting on my shelve, when I needed just three of them for an emergency fixture but have ordered a strip of 50; half watt rated SMD's, the rating is at 60degC junction, so well attainable with decent heat management and not pushing them to the limit). So with the ballast losses it won't be worse than about 120lm/W...

Bare SMD LEDs dont make an optical system. Put them in a system and they will have optical losses too, and probably no less than a Fluorescent with high end reflector system. The LED optics have bigger task, because other than directing the light they also have to diffuse the point sources to prevent glare, while with the FL this already come as a feature of the lamp itself

I just don't get why the industry allows for ballast compatible LED retrofit lamps. It is only to appeal to the apprehension of people to direct-wire their retrofits, which would cut into profits, I guess?

Of course, we have already beat to death the fact that consumerism is the actual underlying motivation for going "green". Truly being "green" also includes reducing material consumption, and using what you have until it is completely exhausted. However, "they" would have us believe to be "green" we NEED to go out and BUY NOW the new "GREEN" stuff. Which is made in China. A very non-Green place. ANd then shipped here on bunker fuel. What a great system!

OK, but, back to retrofit lamps. I have also heard people say LED specific lighting fixture would be better. Yes and no. It would optimize LED performance, sure. But, since they are usually a unitized construction of non-standard failable parts, the problem is that any lighting failure would basically mean binning the entire fixture in most cases since most people are not going to troubleshoot a light fixture you can't even get spare parts for. Which would also lead to the undesirable effect of now having mis-matched fixtures, further forcing a consumer to consider replacing all again to get consistency.
Retrofitting kind of forces manufactures to make exchangeable LED modules, i.e T8, A shaped or PAR lamps for example. They reuse the old fixture, thereby not being TOTALLY as wasteful as throwing away good legacy fixtures. This is why that when I choose exterior lighting, I NEVER buy those LED specific lanterns or flood fixtures. I buy regular PAR flood fixtures or screw base wall lanterns. That way, as LED stuff comes and goes, it is a simple task to exchange LED retrofit bulbs that are standardized to legacy fixtures. Sure, somewhat less "efficient", but still very efficient overall.
This is why I don't get the ballast compatible LED tube thing. Just rewire your old fixture for direct AC! Sure, you MAY need to reconfig the tombstones, but you'll only need to do it once, and direct wire LED tubes can be changed out whenever for relamping/upgrades. And who the heck thinks running a ballast to LEDs is a good idea anyway? penny wise, pound foolish.

If there ever was a time for lighting regulation, I think LED lighting should get regulated right now (I know there is some, but it needs more). 2 regs I'd like to see:
1. NO ballast compatible LEDs.
2. NO non-standard LED fixtures. i.e., all LED-only fixtures should have industry standard form factor modules, the light module and the power supply module, so that at anytime in the future the fixture can be maintained, repaired and/or salvaged.

Direct-wire LED tubes are OK IMO. While I agree, I prefer traditional lighting forms, there is one place in my house where a LED retrofit of some old, rarely used wrap-around fixtures would be very nice. It's just too hard on the fluoros to short cycle them in that application.

If there ever was a time for lighting regulation, I think LED lighting should get regulated right now (I know there is some, but it needs more). 2 regs I'd like to see:
1. NO ballast compatible LEDs.
2. NO non-standard LED fixtures. i.e., all LED-only fixtures should have industry standard form factor modules, the light module and the power supply module, so that at anytime in the future the fixture can be maintained, repaired and/or salvaged.

Any such regulation is completely wrong. It is their money and their business, their decision, their right to make bad decision and so their responsibility to bear consequences. People have to learn first hand, what the consequences of a bad decisions are. Any "protection" will always lead to losing an ability to do reasonable judgment.

A regulation has it's place, when a small benefit for one means way bigger loss for others. So it could be the requirement to collect the things containing toxic substances for proper recycling and not allowing them in landfills or so, so forcing to spend more money for waste management. The users should have the freedom to choose other technology, if someone wants to make it for them.
Or taxes for air pollution from e.g. power generation, even when that means more expensive power. User then has to have the freedom to either go for more efficient lighting, or invest the money into e.g. better house insulation, so saving on AC, or just pay the more expensive energy. His business.
But banning any light formats that is not the case at all, their existence on the market should be driven solely by the demand/offerings basis. If someone wants e.g. incandescents and someone is willing to make them, there should be no one else interfering with them. If the last maker decides to stop their production, the customers have to set up their own manufacture or just live without.

You probably don't want to regulate LED right now because it's the LED equivalent of banning other lighting, which we're trying to get rid of. Think about how the Pro-LED people feel.

You probably don't want to regulate LED right now because it's the LED equivalent of banning other lighting, which we're trying to get rid of. Think about how the Pro-LED people feel.

I don't want to regulate LED's the same as I do not want to regulate incandescents, nor MV's, nor any other light type just because someone things it is inefficient, ot unreliable or otherwise expensive. Sadly, the greenbrainers have already forced the incandescent and MV bans, that does not mean I would not be against any such "revenge" as banning some LED forms because they are "not reliable".
The fact I do see any format as justifiable (in present day or near future) does not mean I want prevent anyone to use it if he sees fit. It is just his decission, he may have many good reasons for that in that particular case I do not know at all. I may just voice my concerns, but the final decision is on him...

Quote from: takemorepills on September 01, 2016, 11:27:32 AM

If there ever was a time for lighting regulation, I think LED lighting should get regulated right now (I know there is some, but it needs more). 2 regs I'd like to see:
1. NO ballast compatible LEDs.
2. NO non-standard LED fixtures. i.e., all LED-only fixtures should have industry standard form factor modules, the light module and the power supply module, so that at anytime in the future the fixture can be maintained, repaired and/or salvaged.

Any such regulation is completely wrong. It is their money and their business, their decision, their right to make bad decision and so their responsibility to bear consequences. People have to learn first hand, what the consequences of a bad decisions are. Any "protection" will always lead to losing an ability to do reasonable judgment.

A regulation has it's place, when a small benefit for one means way bigger loss for others. So it could be the requirement to collect the things containing toxic substances for proper recycling and not allowing them in landfills or so, so forcing to spend more money for waste management. The users should have the freedom to choose other technology, if someone wants to make it for them.
Or taxes for air pollution from e.g. power generation, even when that means more expensive power. User then has to have the freedom to either go for more efficient lighting, or invest the money into e.g. better house insulation, so saving on AC, or just pay the more expensive energy. His business.
But banning any light formats that is not the case at all, their existence on the market should be driven solely by the demand/offerings basis. If someone wants e.g. incandescents and someone is willing to make them, there should be no one else interfering with them. If the last maker decides to stop their production, the customers have to set up their own manufacture or just live without.

Czech Republic, eh? Do you have a feel for the culture in the USA? Maybe we have similar issues as where you live, here "they" like to use regulation to drive consumption, or to create social engineering all in the name of "good deeds" or "doing whats right". If "they" feel it is "right" to ban some forms of lighting, or tax electrical consumption to promote "sustainability" or "green future" then I think it is fair to say that they can also regulate that LED lighting be standardized, and have interchangeable modules to promote reduction of waste by creating products that can be reused and repaired with minimal waste.

Maybe you being from CR you don't see things exactly as we live here. "They" always tell us "it's for our own good", but "their" regulations only make things worse upon closer scrutiny. Basically, our government is full of the biggest liars in the world, I am sure.

I think we may agree the regulation does nothing good at all. And mainly because there is way too much of it already now, having more of it will make all the things only worse.

And regarding the tax on electricity: If the power generation is harming the environment, but not so directly everybody really would really feel that impact, a tax (on the pollution by the power plant) on it is a good motivator for people to think of really using less of it (and not just "I've replaced all incandescents by CFL's, so I'm done with energy conservation"). How they do that, it should be again left as their business. The money is the best motivator to do the things, which lead to the most of the savings in their particular case.

It should be like that with everything: If something pollutes the environment, the pollution itself should be taxed. Not the use pf the products banned or so.