LED direct replacement for flashlight bulbs?

Kinda outta date here. Most of our stuff is old, but it works; or if it doesn't we fix it asap. So is it possible now to buy direct LED replacement for the traditional two and three cell flashlight (and 6 volt lantern bulbs? The only blue-white colour LED have in the house so far is a small 115 volt AC 'night light' in one half of the bathroom GFI. Also a couple of orange coloured night lights in passage-way which may or may not be LEDs or perhaps small neons? The somewhat weird coloured light of some of these newer devices is a bit of a turn-off. Although two of the newer 'coiled' CFLs in relative's garage, along with some eight 48 inch tubes in rebuilt fixtures, do a fine job.

Reply to
terryS
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I don't know of any __replacements__. You could attempt to build them. There are a couple of web sites on replacing a 222 style bulb, I think:

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I don't know of any reliable manufacturers selling these. It might be interesting to do a start-up on it. Of course, if it made any real money you'd get muscled out pretty fast. But it might be possible to do a 'cottage' business out of it?

Besides the obvious issues of making them, LEDs do not have the same dispersion angles or distributions as incandescents. The typical flashlight reflectors may be poorly designed to make the most of the LED replacements. Some experimentation may be required to find a workable LED and relative placement above the bulb base to make good use of the existing reflectors (if that's possible, at all.)

The "white" LEDs can be based on several methods.

One is simply combining red, green, and blue LEDs into a single package and using a carefully balanced mix. That's not usually used for the white LEDs you usually find, though. It takes some calibration of each one to make them a decent 'white' and low-price point manufacturers would hate that. So I wouldn't expect this.

Another depends upon phosphors for fluorescence and uses a blue LED to stimulate them. There are literally thousands of rare earth phosphor mixtures and probably hundreds of practical ones. They can be combined with other phosphors or used by themselves. Of those, only a few are selected for most commercial LEDs. But there ARE differences. Some will produce a different "white" than others and you could try to find web pages or reviews that talk about this aspect before buying. I don't buy them, so I have almost no opinion about it. Don Klipstein at misty.com might be a good bet for some reading... or perhaps he may post here about it.

Like everything, you have to do your work to find a product you will like over the long haul.

I don't have a high opinion, yet, of CFLs commercially available in my area's stores. Mostly, my complaint is about service life and versatility. Many cannot be used in places you usually expect a light bulb to provide long service -- for example, in sockets exposed to outside weather or in enclosed or semi-enclosed ceiling fixtures.

To add a recent story to this, my wife asked me to replace out a desk lamp's bulb (the old one was a CFL that no longer worked.) So I got two replacements out of the drawer where we keep bulbs and compared them both while she watched and gave me her opinion.

One was a Philips 40-watt/120V incandescent flood lamp with reflector and the other was a 65W CFL replacement for similar reflector bulbs, claiming that it "uses only 15 watts", "uses 75% less energy than ordinary 65W reflectors", and "lasts 5 times longer than standard 2000 hour reflector" bulbs. That latter is FIET Electric's Conserv-Energy bulbs that I get from Costco, claims they "can be used in high temperature applcations such as insulated ceiling airtight recessed can fixtures," and claims an output of 750 lumens and a life of

10,000 hours. (They state they cannot be used in dimmers.) Compare this claim for 750 lumens with the Philips' 40-watt incandescent bulb, their "Halogena 40W 120V" mentioned above, which claims just slightly over 600 lumens (610, initially.) The Philips' unit claims "fully dimmable" (not that I cared in this application) and 3000 hours of life (which I believe) and that it doesn't contain mercury and that it is "ideal for table lamps, floor lamps, recessed fixtures, and track fixtures." I cared about the "table lamp" application, obviously.

Neither of us had any question at all once we tried the two. The

65W-equivalent CFL claims 750 lumens, while using 15W of energy. The 40W incandescent claimed 610 lumens, while using (of course) 40W of energy. However, the 40W incandescent was MUCH, MUCH brighter by our judgment. Instantly obvious. So I went and pulled out a 25W flood dimmable, incandescent Halogena (fancy looking) from Philips I also had in the drawer and used that. It was still brighter than the 65W-equiv. CFL, by our mutual judgment and far more usable for reading at night. The 25W Halogena claims about 300 lumens, initially. It was still quite a bit brighter than the above mentioned CFL unit.

In short, some CFLs (those from FEIT that we tested) are probably about as usable by us for reading at night as the same wattage halogen incandescent (perhaps 15W to 20W -- I'm guessing from experience that the 20W halogen would probably still look brighter, though.) I do NOT find the CFLs to be worth the trouble in many applications.

However, I _do_ use 4' fluorescents a lot!! They've been around a long time, work as expected, and I am generally happy with them. Where I can use them, of course.

This was quite a digression and I apologize. But you brought up the CFLs above, when talking about LEDs, in discussing their usability. CFLs and fluorescent bulbs use rare-earth phosphors. So do "white" LEDs. Not necessarily the exact same phosphors, but the idea is still there. And so are the concerns about color and usability. So I hope the digression is more of a warning to do your research about this, than anything. If you find a product or decide to make a replacement on your own, do some research to make sure it fits what you want.

Jon

Reply to
Jon Kirwan

About five years ago, I got a plug-in replacement for my 2AA Maglite. That preceeded Maglite having their own LED flashlights.

But the replacement was specific to that flashlight, I'm sure there was a different replacement for other Maglites. I don't have it handy, but if I recall properly, one took out the original reflector, and this whole unit fitted in, complete with a new reflector.

The odd thing is, a decade ago, there was lots of discussion here about LED flashlights, they either not being available or expensive, so people went through the effort. I remember about five years ago, buying a bike light because it was a cheap LED flashlight, it gave off decent light and was cheaper than equivalent LED flashlights at the time, though it was cumbersome to turn on and off since there was a flashing mode activated with the same on/off switch.

Now, LED flashlights are outright common, and I suspect the days of incandescent flashlights are limited, certainly for everyday use. I bought a 3AA LED flashlight last year for four dollars, and it had 9 LEDs in it, and it's better than the 1 LED Maglite replacement that cost ten dollars or so.

Flashlights tend to be pretty inexpensive, so buying a new flashlight isn't going to be much cheaper than an LED replacement, and one isn't going to lose much by retiring the incandescent flashlight. There's one of those in the kitchen here, and despite it using two D batteries, it's got a weaker light than any of the LED flashlights I have now, and less worry that the batteries will be too weak to run the LED.

Michael

Reply to
Michael Black

Good arguments for the OP to consider.

The OP wrote, "Most of our stuff is old, but it works; or if it doesn't we fix it asap," and I took that to mean that there is a certain mind-set operating here. So I responded in that vein.

Jon

Reply to
Jon Kirwan

,

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Thanks Jon. Yes smart to identify that 'mind-set'; the initial reaction, here, to anything that doesn't work, or doesn't work right, IS to fix/repair it!

And looking around the house, for example, many of our items are well used and/or were obtained free or second hand, or for a bargain price because they were easily fixable or someone else didn't want them! But were still operational.

Our current dishwasher was free (minor repair needed), also our third cooking stove. The wood burning stove we got for $200 and hooked up ourselves (It passed fire-dept and insurance company inspection). The clothes washer was repaired using the tub out of a similar machine scrapped by a relative! Etc.

And subscribers to do-it-yourself forums may understand the sense of pride that comes from making something work correctly. It also inculcates a certain ability in life to cope with almost anything that can occur domestically. And is far cheaper than always buying new. So the bank account has been in the positive region for the last 20+ years or so; assets are on the plus side, everything is paid for and nothing is owed to anyone! So who cares if the cooking stove is 15 years old and we are its second/third owners. It cooks and bakes fine btw.

We built most of this house ourselves in 1970 (self and two carpenters) and have modified it further to also house a small business; over the last 40+ years.

But 'fixing things' may not always be the 'best' solution; and, as someone pointed out, one may be able to buy a complete new flashlight for about as much as refitting an older one with an LED!

But it really goes against the grain to throw away something that is not 'completely' broken. Hard; but am learning!

The habits of a lifetime; based originally on growing up during the rationing and shortages of WWII and an otherwise frugal upbringing are hard to break! Fix your own shoes? Yes. Dig and fill in soil latrines, yes. Repair your own TV and radio etc. of course ................ one of the few things one doesn't do these days is tubeless tire repair; that seemed to go out when tire tubes ceased! Drains blocked ........ get out or borrow the rods to ream it out. Hoping it's not tree roots that deep in the ground!

So a question about LED replacement bulbs for a flashlight seemed rather simple?

Vehicle-wise; recently we replaced the reverse/backup light switch on the pickup and installed a new differential air vent to replace the one that was blocked by dirt or something.

Reply to
terryS

In , J Kirwan said in part:

And so I do!

Most white LEDs have a blue-emitting LED chip coated with a phosphor that produces a yellow/yellowish output that is at least somewhat broadband. The phosphor does not absorb and convert all of the blue light from the LED chip, but allows some to pass through. The combination of the blue light passing through and the yelloe/yellowish light produced by the phosphor is white/whitish.

Usually, the phosphor is or has been a "YAG" type ("yttrium aluminum garnet") doped with whatever it needs to do the job the way it has usually been done. In most of the history of doing this, the phosphor has been "lossy" to an extent beyond that of "Stokes Loss" to such extent that lumens out per watt in is maximized by deploying the phosphor thinly enough to allow through enough blue light to make the resulting shade of white slightly on the bluish side, usually with color temperature around

6000 K. Color rendering index of this formulation has usually been 70-75.

In recent years, this phosphor has had its non-Stokes losses reduced enough to maximize lumens/watt with a less-bluish shade of resulting white, with color temp. around 5000-5500 K.

A slightly-somewhat differing phosphor formulation emerged recently, with its yellow-centered band narrowed somewhat to reduce output in longer red wavelengths (and symmetrically reduced in deep-green wavelengths around 520 nm) in favor of yellow or a greenish shade of yellow. This phosphor formulation has tended so far in my experience to have lumens/watt maximized (with limitation of blackbody-like overall color) when color temperature is around 5000 K, and color rendering index is around 65.

Warmer color white LEDs require their phosphor output to have their spectral output shifted a bit to longer wavelengths (away from 555 nm at which human photopic vision is most sensitive). I find this countered by ability to have final output using more of yellowish phosphor output that human photopic vision is more sensitive to, and less of leaking through the blue light that human photopic vision is less sensitive to.

I have found "somewhat" that optimum color temp. for maximizing lumens/watt for an artificial light source free of IR and UV is around

3500 K - fairly warm. This requires an adjustment to something higher due to Stokes loss in the case of blue LED chip and 2-dimensional variable of how much to convert and what shade of yellow to convert the blue to - I am guesstimating 3800-3900 K at this monent, but I consider possibly as high as around 4100 K, not-that-warm.

Since phosphors have losses other than Stokes Loss, lumens/watt is optimized, when restricted to blackbody-like overall color, when color temp. is something higher than the 3800-3900-to-maybe-even-4100 that I consider to be optimization if the only phosphor loss is the "Stokes Loss".

I might want to sometime reduce my estimates of "optimum color temp." to around 3300 K if the phosphor had no losses, and around 3600 K if the phosphor's only loss was the "Stokes Loss". Phosphors have other losses, including quantum efficiency short of 100% of photons absorbed, as well as photon absorption not leading at all to fluorescence increasing with degree of phosphor deployment.

So I consider "pie in the sky" to be phosphor maximizing lumens/watt when deployed to extent that achieves 4100 K.

Need for color rendering index higher than 65-70/whatever will reduce lumens/watt, and desire for CRI at least 82 appears to me to be when color temp. is warmer/lower, mid-3000's to upper 2,000's. Phosphors used so far to achieve higher color rendering index "warm white" LEDs appear to me so far to usually be a mixture of ones achieving a diversity of peak wavelengths ranging from mid-green to somewhere in/near "orangish red", maybe as long as about 630 nm or so which I consider a "hardly orangish shade of red", though such a reddish phosphor ingredient likely appears more orangish than that due to human vision's bias to wavelengths shorter than 630 nm).

At this point, I snip everything afterwards, and I did say above I-hope-well-enough that I was quoting and responding to only part of the post that I was responding to ... :)

- Don Klipstein ( snipped-for-privacy@misty.com)

Reply to
Don Klipstein

Here's one: Kinda pricey! (Use the tiny link.)

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--
Virg Wall, P.E.
Reply to
VWWall

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Try this one:

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-- VWW

Reply to
VWWall

Yes, you can buy LED replacements for most flashlight bulbs:

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The PR2 (flange base) replacements are available for 1 to 6 violts DC, so bulbs to fit from a single cell flashlight to one using the 6 volt "lantern" battery (the 30+ year old red Eveready floating lantern).

John

Reply to
news

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I got some replacesments for PR2 or PR3 a year or two ago at WalMart. It was about $5, so it is probably cheaper now. Our WalMart kept them near the sporting goods department.

Reply to
jfeng

A...

Thanks for the links/ideas for LED replacements for 'regular' flashlight bulbs.

Reply to
terryS

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