High Wattage Halogen Replacements

OK, if you need to put a huge amount of light into a small fixture, then I do agree with you. But, if you have the space to put a bunch of LEDs in an "area" source, they can work quite well. Streetlights are now being done with LEDs, for instance.

I've built two replacements for dual 48" fluorescent tubes in our kitchen, and they work great. 2000 lm for 21 W drawn from the AC mains. And, they run much cooler than even fluorescents. Also, all the light is PROJECTED in a controlled direction, which is often much better than incandescents or fluorescents that put out light in all directions, requiring diffusers and reflectors.

Jon

Hey, thanks for reposting that. I was looking at a burned out florescent bulb that is over my fish tank, and I was thinking that I should replace it with some LED's.. stuck into the same hood. Is that power supply a fixed current? (Do I have to buy the dimmable version to change current?) I could mix in some Red's and blues to help with plant growth.

350 mA looks like a pretty standard current.

George H.

The LEDs I found have "water proof" PSUs available. Not sure why the PSU needs to be water proof and not the LED, lol.

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Rick

Not smoking anything. You do not have to believe, but if you do a little searching on the internet you will find I am right.

Dan

I'm not sure what "right" means in this context. I have seen bulbs of various wattage and I know a 500 watt bulb which should be 10,000 lumens does the job. A 200 watt bulb does not. A 200 watt bulb is even brighter (typically) than a pair of 100 watt bulbs (typical 1600 lumens each) because of the way they build incandescent bulbs. It does not matter to me if the eye is sensitive on a log scale or not. I know what I can see.

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Rick

You might think about buying some LED lamps from WalMart. They were selling 800 lumen LED lamps for $2.44 each. They use 8.5 watts. And are not dimable.

But WalMart has dropped the price to $2.18 and they are closing out all the compact fluorescent bulbs. Even if you do not use them for the fish tank, they are worth using in a lot of locations. Cheaper than T-8 fluorescents.

Dan

I looked at these devices. I'm a bit unclear about the dimming. Rather than working with conventional dimmers, these seem to work with a special dimmer that is designed for a separate 0-10 volt circuit. The TRP literature suggests the dimmer is just a variable resistor of some value. They recommend a Leviton IP710 dimmer control. But I have been down this road before with an LED recessed lamp which called out specific part numbers for compatible dimmers. The one I bought didn't work well. This part number is not a complete part number. Leviton indicates it requires a suffix to determine the type of load or control method. Which is correct for this supply, the IP710-DL or the IP710-LF?

I might use this for something like under cabinet lights, but the PSU is far too large to use in the torchiere lamps.

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Rick

Yeah sure.. I've been using led "bulbs".. For the fish tank, I want to just shoot light down into the water. The directivity of single leds looked right. I can certainly buy an led fish light for less than I can make one for... But that's no fun at all.

In some ways (lighting-wise) I'm more interested in plants*. They want ~ 430 and 650 nm.

George H.

*I like to see my aquarium as a little ecosystem. I input fish food and light... and water flow through the filter... bacterial "digestion".

I don't expect an answer to this question: If I wanted to stimulate plant growth, should I try and spread out the spectrum of an led... I'm thinking like a slow PWM so that it heats up some. Or maybe that doesn't matter?

GH

OK, I bought some Thomas Research Products NON-dimmable 25 W LED supplies from Digi-Key, Thomas part # LED25W72-0350. That decodes to up to 72 V at

350 mA regulated current. If you add "-D" to the end of the part number, it is "analog" dimmable. If you add "-PD" it is PWM dimmable. They aren't real specific about how these dimming options work, but it looks like analog dimming is just a pot, and PWM dimming requires a 10 V PWM pulse, 200 - 1000 Hz. These things are pretty expensive, but are isolated off-line supplies and are supposed to be almost 90% efficient. I've had 2 of the non-dimmable ones running in my kitchen for about 2 years, and they have worked fine.

Jon

Well, if these things are REALLY energy efficient, and will last many years, then I don't mind aying a bit for them. I did install these in the place where they are on more than any other lights in the house. Also, I replaced some ANCIENT magnetic ballasts that were probably beginning to go bad. They turned out to be HORRIBLE power hogs, drawing 103 W for two 48" tubes. If I'd known how bad those ballasts were, I might have done something earlier!

So, on 2 of the 3 double-tube fixtures in the kitchen, I have cut the power consumption from 103W each to 21 W each (measured with a real power meter.) (I will have to do the last unit when I get a chance.)

At the time I started in on this project, I went through the list at Digi- Key, looking for the best Lm/W, and then picking one that was VERY efficient but just before the price went crazy. I was also looking for units that would be possible to mount with standard soldering tools.

And, with 2 Sq. Inches of PC board copper per LED for heat dissipation, these LEDs run quite cool. I'm guessing the dies are running maybe just a hair over 50 C with the lamps all covered up in the ceiling fixture. The PC board right next to the LEDs stays below 40 C. So, I expec these to last a LOT longer than mediocre Chinese consumer-grade lighting that runs so hot that you don't dare touch it until it has been off for minutes.

Jon

I don't expect an answer to this question: If I wanted to stimulate plant growth, should I try and spread out the spectrum of an led... I'm thinking like a slow PWM so that it heats up some. Or maybe that doesn't matter?

GH ==========================================================

Some plants only need the red, some need both blue and red. This is the datasheet for Sylvania's aquarium Gro-Lux fluorescent bulbs, that shows the action spectrum for chlorophyll and the spectral output of the Gro-Lux bulbs:

They also have Gro-Lux bulbs for plants but to me the spectra are pretty similar (and I found this one first on Google :-)). From the reading I did a few years ago the normal setup is to just use blue and red LED's whose spectral output is centered on the chlorophyll spectrum, and if you really care you need to vary the red/blue ratio to find the optimum for your plants.

----- Regards, Carl Ijames

Yes, the plain unit is fixed current, the dimmable one (add -D to the end of the part #) is dimmable, I'm pretty sure, using just a pot. Costs $2 extra. There are, of course, tons of these LED lighting regulators, it looks like Digi-Key now has some more choices that are less expensive.

Jon

Yes, I found that when I looked up the model numbers you had supplied. The problem is figuring out the controls to go with the 10 volt analog dimming. Leviton is mentioned on one of their pages, but Leviton is

*really* bad at not telling you much technical info and there are two models with the 10 volt dimming option for different uses. Not sure what the difference is. Leviton figures either you already understand it all, or you don't need to know.

These PSUs are too large for the torchiere lamp. I think I'm going to get the eBay 50 watt light and PSU for $10 and give it a try. I've got one vendor who I think is saying it will work with a conventional dimmer switch which is already built into the lamp pole. I don't know if I believe him, but it gives me an excuse to return it if I don't like the result.

I still am looking for some under the cabinet lights. The PSU you describe might be a solution for that. I'd need to run wires inside the cabinets (I guess that can be made to work neatly). I don't know that I need a dimmer but it is always nice to have if you want to use it for "mood" lighting. A friend had glass front kitchen cabinets and installed lights inside. It was a very nice effect.

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Rick

Hi

Sure, for a light with sufficient area, LEDs are ideal. The number of lumens that you can get is (excluding forced air cooling) essentially proportional to the heatsink area that you can provide. In fact I also have an LED light, built into what was initially a light designed for halogen lamps. But for this I have put the LEDs on 2 aluminium plates each about 40 x 3.5 cm in size. That's enough for some 35 W, which is still somewhat below 2000 lm total (Luxeon LEDs from the mid-2000s). More modern LEDs would probably give about 3000 lm at the same power.

A torchiere lamp has some area, but its construction is not made for good convection, rather the opposite, as there is almost no surface of reasonable size that could be oriented vertically. Putting all LEDs on a big circular metal plate and the plate inside the torchiere lamp's half "UFO" shape will just shield the plate from any natural air currents.

With modern efficient LEDs, I think, one could get 2500, maybe 3000 lm that way without overheating the LEDs and without using fans, but much above that range will be difficult (will likely need replacing of the entire "Half-UFO" with a one-piece heatsink of similar shape).

For a mood light, that's more than plenty, and may even need to be dimmed. For a work light, I would consider it somewhat low, and prefer another 2000 or 3000 lm in addition.

Maybe something "hybrid" would work. The "R7s" sockets for the original halogen lamps happen to be mechanically compatible to "Rx7s" sockets for

70 W discharge lamps, the only differences being internal isolation clearances and thicker wire isolation. That would leave the possibility to put a bright discharge lamp in the middle, where the halogen lamp would normally be, with no modifications to the original construction, and also add an outer "ring" of LEDs for low power "mood light" use. The LED ring could even be made from warm white LEDs, while the main lamp (the discharge one) would likely be neutral white, so that one could have different light temperatures as appropriate to the intended use.

Actually I have replaced the halogen lamp in my torchiere with a 70 W discharge lamp years ago, and kept the original socket, just made sure that there were no metal pieces in the way, where wider clearances would be needed for isolation. But this is only for a work light use. It can be "dimmed" to 50 W (the electronic ballast provides 70 W, 50 W and 35 W as discrete selectable power settings), but not continuously, and 50 W is still quite bright. The ballast could in theory be set to 35 W, but a

70 W discharge lamp doesn't maintain a good white balance at so low a drive power, so that leaves only 70 W and 50 W settings where it will actually work well. Since I never intended to use it as a mood light, I haven't installed anything to get that function, but if that was ever needed, I would probably have tried to put a ring of lower power LEDs on the periphery, while keeping the main discharge lamp in the center.

Dimitrij

That's easy enough to fix. It would justify purchase of a bench punch and allow me to explore my creative side. I remember metal lamp/candle shades with patterns of holes. That might look very good in the metal shade of a torchiere lamp.

Is this based on any calculation/experience or just a seat of the pants feeling?

Lol, I'm sure 10,000 lumens will *not* be mood lighting... maybe. I have a steep cathedral ceiling and if I put it near the high point of the ceiling it my light the entire room "gently". Right now it is near my desk at the wall with the lowest point of the ceiling.

Interesting idea, but these bulbs require a ballast which is much bigger than the LED supply. They are also a bit pricy. The LED/PSU combo I've ordered is less than just the bulb. I'd hate to find out what the balast costs.

But wait! There's more... I was reading a GE data sheet on these bulbs and they take three minutes to warm up! They give off virtually no light for nearly a minute. Sounds more like industrial lighting to me.

I'm not sure what the advantage of this lamp would be. The cost of the bulb and ballast would likely swamp the cost of the lamp fixture. I can see using a couple of these mounted high on the wall to shine upward. I may look for fixtures using these bulbs.

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Rick

Good idea. But make sure that the LED plate gets some way for the air to pass alongside its surface. Maybe add some holes too, so that the air space under the plate is not too enclosed from above, and maybe add some vertical fins around holes, to get most out of the chimney effect. That should increase the thermal load capacity considerably (although it may still be on the low side from a LED standpoint).

No, it's not calculated. But I have that 35 W LED light with the two parallel aluminum plates for cooling. The plates are oriented such that there is a "chimney" between them and the LEDs look sideways from each plate. The LEDs are 12 in total, 6 on each plate, the plates have a space of about 1 cm between them and are hanging basically like this:

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The plates already get quite hot and while the LED temperature is not

A circular plate for LEDs that can be put into a torchiere lamp would have a total area of a similar order of magnitude, just a little larger most likely, but it would be oriented horizontally and not vertically and it would be at least in part shielded from air currents from below plus it wouldn't have any chimney effect to speak of. From my gut feeling, that would put it in the below 20 W power dissipation class. Maybe, with holes, in the below 30 W class, but then that would mean running the LEDs at something like the datasheet maximum junction temperatures. Again, I have no way to measure or calculate this (that would require thermal models of the various parts including geometry and air currents, which would be decidedly non-trivial), but that's what my little experience of dealing with electronics heat dissipation.

Thermal 20 to 30 W corresponds to some 2000 to 3000 lm LED light with new LEDs (in my old light with the aluminum plates and the Luxeon LEDs from ca. 2010 it's less, of course, rather like 2000 lm from 35 W).

Well, 10k lm is a hell of a lot! And if generated with LEDs, that would require some serious active cooling (if you intend to actually get real

10k lumens). 10k Ebay lumens claimed by a seller from some place in the woods will likely turn out difficult to attain if one cares to measure.

To compare, 10k lm is the equivalent of a 100 W discharge lamp (Philips claims 14200 lm for a modern ceramic 150 W). I've seen an older, less efficient version of a 150 W discharge lamp, one that still had a quartz and not a ceramic burner, and it was painfully bright. Really painfully bright, no way to look at it. It must have had some ca. 12k lumens or thereabouts, and I don't think that I would even have considered that much for use in a living room.

Here in Germany a 70 W lamp (CDM-TD 70W/945) is about 15 EUR and a switchable 35/50/70 W ballast (HID-AV C 35-70 /I) is about 30 EUR.

Yep. That's the downside. The first split-second they flash up from the ignition pulse, then the first half minute they hardly make any light.

Their intended use is indeed industrial and architectural lighting.

There is another downside, they can't hot-restrike. That means, if you turn one off, you will have to wait 10 to 15 minutes for it to cool down before it can be switched on again (the discharge medium temp and pressure have to drop down again, before an arc can be re-ignited).

Another caveat is UV radiation. Philips lamps have UV filters inside, and Osram ones too, but not everyone makes filtered discharge lamps. Some (particularly cheap) manufacturers' lamps have no protection and require external UV filtering. If that is not provided, they can emit enough UV to be dangerous to the eyes.

Well, nowadays the advantage would be small. In the early-2000s, when I put together this thing, LEDs were used for small lights in instrument panels. Incandescent bulbs were not yet banned, and the most common energy-efficient source of light for home use was a CFL. At the time, I've had a torchiere lamp with a 300 W halogen, but I did not like the amount of energy that it took. CFLs would not fit and LEDs for general lighting applications were non-existant. It was the time when low power (less than 250 W) discharge lamps were gaining traction in industrial and architectural use, and the prices for discharge lamp ballasts went from outrageously expensive to merely somewhat expensive. I found that a

70 W lamp (with a quartz burner back then) could be had for under 20 EUR, and I had plenty of various old fluorescent ballasts that I could parallel to get about 70 W total. An ignitor could be made from some junkbox parts. It turned out to work, and the light output was to my liking, but the lamp would flicker (the ballast contraption did not fit exactly to what the lamp expected). Then I kept the lamp, but replaced the contraption with a new electronic ballast. At some time, when the unreliably built stand of the cheap torchiere broke, I got a new one, and moved the existing discharge lamp and the electronics in there. Some years later, when the lamp started to get blue-ish (it was a quartz lamp with not a very good longevity), it got replaced with a ceramic one and while at it, I also changed the ballast to a new one that could be switched over to either 70 W or 50 W.

It still works, but its use is, as they say: "for hysterical raisins" (for historical reasons).

Just 2 - 3 years later, LED lighting really took off, and LED household lamps became commonly available. Now they are better options, but as you certainly have noticed, most of them are designed with different geometry in mind, and they tend not to fit into old torchiere lamps.

Dimitrij

One has to wonder if a collection of LED's plus a small fan, such as found in PC's, would still be way ahead of the efficiency of CCFL's. ...Jim Thompson

-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

| 1962 | The touchstone of liberalism is intolerance

The LED is small, two inches square. It will need an aluminum heat spreader which can have fins by cutting the outer portion radially and twisting the fins upright. Lots of surface area and lots of space for air flow.

Actually, I've ordered the 50 watt unit which is some 5000 lumens.

I have no idea how bright a discharge lamp is. I have a 500 watt halogen though and they are claimed to be 10,000 lumens by the bulb maker. That is what I would like to use. The room is about 30 x 15 feet and the ceiling slopes from normal 8 foot to 17 foot over the 15 foot run. Lots of ceiling to reflect light off.

I have no idea why you would want to look directly at *any* of these lamps, anything over 75 watt incandescent is too bright for me.

Compared to $10 US.

That may be a deal killer for any home use.

I'll let you know how my experiments work out.

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Rick