I have some torchiere lamps with burnt out J1 style halogen bulbs. Rather than replace the bulbs with new ones I was thinking of trying to find more efficient replacements. Some are 300 watts which seem to be around 6,000 lumens and others are 500 watt which are around 10,000 lumens.
I found some LED bulbs to fit the sockets, but the highest lumen rating is only around 1,000 or about equivalent to a 75 watt incandescent bulb. Am I unlikely to find an LED replacement that is anywhere near as bright as the bulbs I'm replacing?
There was a recent discussion on making your own LED light. Is that what I'll have to do?
I have a torchiere that was a Halogen, but I converted it to a dual edison base. I'm not running mega lumens either, but you should consider a conversion.
After doing some searching on high output LEDs, I found some modules that will output up to 9,000 lumens, powered by 3 amps at ~32 volts. I'd have to build a power supply for it if I can't find one. If I do a conversion, that is the way I would go. I like the light to bounce off the walls and ceiling. I don't think a couple of 100 watters will be the same as the 500 watt bulb I'm used to.
One thing to remember is that people have a log response to light . The same as the response to sound. So two hundred watts will not be perceived as a lot less bright than 500 watts. i.e. 250 watts of light will be 3 db down from 500 watts.
In the 2000 and above lumen category, I don't think that LEDs will get you any kind of reasonable solution.
For 600 lm and below, accent lighting, "mood lights" and such like, they're quite ok, and that is exactly where their use is intended.
But in the thousands of lumens, they're the wrong tool for the job. This lumen output category traditionally was - and still is - best served by high pressure discharge lamps.
Trying to shoehorn LEDs in there usually results in wasting lots of circuit real estate and disproportionate costs on cooling while only achieving mediocre performance.
If you want to replace a 300 W halogen while maintaining reasonable lumen output, consider using a 70 W ceramic HID (like Philips CDM-TD
70W/942) with an electronic ballast instead. That's good for 6000 lm and has practically the same size as the halogen it would replace.
But, if you decide to go that route, do consider mounting a hard glass plate above the lamp in case there isn't one already in place. While electronic ballasts do monitor the lamp voltage, and usually do a good job at preventing the lamp from shattering through overload, there is of course no guarantee, and it can happen that a HID lamp shatters.
Not sure what you are smoking. I know what a 500 watt light looks like and it is a *lot* brighter than even a 300 watt light. I use these lamps to throw light on the ceiling which in turn lights up the room.
These lamps are typically used with a dimmer. The setting will normally be in the below-100Watt range for a mood light, and when you need to work, want to read, etc you can crank up the light level. (of course this is extremely inefficient because at lower power the efficiency of a halogen lamp drops, worsened by the fact that the glass may blacken because the temperature is too low)
I have one of those myself and indeed there is no good replacement available. It has to be dimmable, it has to fit in the existing socket. The discharge lamp is no solution.
When it failed a few months ago, I was able to find a replacement halogen lamp that is claimed to have a bit (20%) better efficiency than the classical lamp that came with it, and thus a corresponding lower wattage. Unnecessary to say that in practice this is not true and it emits less light than the original when at full power. But that is rarely used.
I asked that vendor about drivers and was given a link for a $30+ water proof model. I nosed around some more and found a number of vendors who sell the lamp with a driver. The 50 watt model seems to be the closest to what I can use. The modules for the 100 watt lamp are a bit large.
I've asked if the drivers are dimmable, but I am guessing not. I like the dimming feature on the torchiere lamps. I'd hate to have to give that up.
Could a simple MCU be used to chop the DC current to the LED chip? It could sense the dimmer voltage to detect the desired setting and duty cycle the LEDs appropriately. Not sure what the chopping would do to the LEDs or the driver board.
Dimitrij's comments are qualitative rather than quantitative, so I can't judge how true they are. "I don't think that LEDs will get >> you any kind of reasonable solution", "But in the thousands of lumens, they're the wrong tool for the job". It is only $10 to get one and try it. My main concern is heat, but the lamp fixture may make a good heat sink, so we'll see.
I'd recommend making your own. Consumer-grade stuff is really crummy. The Cree 1W LEDs are a good deal, 102 lm/W for about $1.59 each in small quantity. I made chunks of PC board material to act as heat sinks, with about 2 sq. inch per LED. See
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for a picture and some info, including some part numbers.
These have been running in my kitchen for a couple years. With the commercial LED power supply, I am running 20 LEDs in series, and it draws 21 W from the mains, measured with a power meter. LED current is 350 mA. This should be delivering about 2000 lumens, which is an excellent replacement for dual 48" fluorescent tubes.
I would think with some design work, maybe you could make up a round plate with the LEDs on it and mount it into the existing lamp. I'm a little skeptical about the 10K lumens, that would be nearly blinding.
I haven't found any drop-in solutions commercially available for this, unfortunately. I haven't even seen any LED torchieres sold commercially which can match the brightness of a halogen torchiere.
The problem seems to be heat dissipation. Halogen torchieres use a physically small bulb, which runs (by design) at an extremely high temperature and is cooled largely by radiation. LEDs need conductive or convective-air cooling, and can't run anywhere near as hot as a halogen without committing suicide.
My thumbnail guess is that to get a lumen output equivalent to a
300-watt halogen, you'll probably need somewhere on the order of 50-60 watts of LED power, with 40-50 watts of heat to dissipate. Packing that much LED into the space of a 300-watt halogen tube would require fan cooling (as is included in some high-wattage commercial LED bulbs in the "200-watt and above equivalent" class).
For a torchiere, I'd guess that a better approach would be to remove the existing bulb socket entirely, and build some other sort of LED mounting. Maybe an aluminum plate 6-8" in diameter, with multi-watt LED emitters scattered across it. The plate would act as a heat spreader and radiator... maybe add some heat sink fins between the LEDs to improve heat dissipation into the air.
I've seen one Instructable where somebody removed the halogen socket, wired in four or five ceramic medium-base light sockets with pigtail leads (all in parallel) and then installed 75- or 100-watt-equivalent LED bulbs and just let the bulbs lie flat on the torchiere reflector. Klugy, but I suppose it's workable.
The 500 watt halogen bulb is rated for 10,000 lumens and, yes, it is blinding. Heck even a 100 watt bulb is blinding.
At $1.59 each, the Cree 1W LEDs are far too expensive. I believe they are using 1 watt LEDs in the bulbs I've talked about elsewhere in this thread. If nothing else those seem to cost only $0.05 ballpark since the 100 watt bulbs have 100 LEDs (10 strings of 10).
For a couple extra $ the commerical LED supplies can be had with a dimming option. You wire a pot to two wired from the supply and mount the pot somewhere convenient on the fixture.
Even if your LEDs are twice the efficiency of the halogen, they'll get hot. The halogens like heat (it's required for long lamp lifetime), and work best on AC. The LEDs need effective coolling, and work best on current-regulated DC. The halogen radiates in all directions and your lamp reflects that light appropriately. LEDs radiate into a hemisphere, and some have lenses attached for narrower output beams.
Your project won't be successful in using much of the torchiere lamp you have now. It's gonna be a better lamp if you start from scratch.
I haven't found any drop-in solutions commercially available for this, unfortunately. I haven't even seen any LED torchieres sold commercially which can match the brightness of a halogen torchiere.
The problem seems to be heat dissipation. Halogen torchieres use a physically small bulb, which runs (by design) at an extremely high temperature and is cooled largely by radiation. LEDs need conductive or convective-air cooling, and can't run anywhere near as hot as a halogen without committing suicide.
My thumbnail guess is that to get a lumen output equivalent to a
300-watt halogen, you'll probably need somewhere on the order of 50-60 watts of LED power, with 40-50 watts of heat to dissipate. Packing that much LED into the space of a 300-watt halogen tube would require fan cooling (as is included in some high-wattage commercial LED bulbs in the "200-watt and above equivalent" class).
For a torchiere, I'd guess that a better approach would be to remove the existing bulb socket entirely, and build some other sort of LED mounting. Maybe an aluminum plate 6-8" in diameter, with multi-watt LED emitters scattered across it. The plate would act as a heat spreader and radiator... maybe add some heat sink fins between the LEDs to improve heat dissipation into the air.
I've seen one Instructable where somebody removed the halogen socket, wired in four or five ceramic medium-base light sockets with pigtail leads (all in parallel) and then installed 75- or 100-watt-equivalent LED bulbs and just let the bulbs lie flat on the torchiere reflector. Klugy, but I suppose it's workable. ===========================================================
Something like that would also allow "dimming", if you brought out individual switches for each bulb, or if the LED bulbs were dimmable and your dimmer could handle the total LED current.
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