This weekend we experienced a power failure, and the bulb on my conventional 2 D cell flashlight burned out. Fortunately I had a spare PR-2 on hand.
For a replacement I went to my local hardware store, then Home Depot and finally Sears. Surprisingly none of these places today sell ordinary PR-2 flashlight bulbs. In desperation, I came from Sears with
2 HPX20 bulbs, Xenon, which are stated to work with any standard 2 D-cell flashlight.
Fortunately I have a good supply of the PR-13 bulbs used in the 6-volt lanterns, although the stores do sell the 6-volt batteries for these things. I purchase one of the batteries at a cost of about $9.00, while the last one I purchased was priced at $3.95.
Isn't that the century old device that we replace with an LED?
The replacement LED assembly in my AA Mini MagLite has half the lumens of the original krypton bulb, but gives 10 times the battery life - and retains the beam focus capability.
White LEDs are *cheap* - You need a little over 3 volts to operate them (fine in the 6volt lantern) and a simple boost circuit for the 3 volt (2 cell) lights.
18000mcd 10mm White LED (about the size of the end of a Sharpie marker) $8US for 20, including shipping.
13000mcd 5mm White LED (half that size) are $12US for 100, including shipping.
At 12 cents each, I'm adding lights to the inside of a closet door (one LED for each shelf) and anywhere else the wife wants more light. Low voltage (under 5 volts) lighting at 20ma per LED is safe and easy to do.
John posted: "Isn't that the century old device that we replace with an LED? "
John, almost but not quite. The LED flahlights are nice, but limited in their utility. I'd guess that the problem with them is that they are too monochromatic, plus they tend not to throw sufficient lumens. This makes them a bad match for practical illumination for a human eyeball. :-)
For emegency lighting and close work in dark surrounding, I far prefer my old Rayovac flashlight with its PR-2 bulb. For serious power outages I still use a Bernzomatic propane lantern with its radioactive gas mantle. No homeowner should be without one of these. It provides equivalent illumination as the Coleman gasoline powered things, but without the mess or the fumes. Mine is still functioning on the cylinder of propane that I purchased back around 1975, and you would be surprised to learn how often it has been used. (Do they even sell these things today?)
When the electricity has been out for more than 4 hours, it's time to haul an old no-name 3-Kw generator out to the driveway and connect it to the house with the so called "suicide cord", of course making sure that first the main breaker to the house has been turned off. In years past this old rig has powered the house for sometimes 3 or 4 days at a time (in Fairport, NY during winter). It can get pretty cold in Fairport, NY, and many of the furnaces don't run without electricity. :-)
As a high-tech guy myself, I learned to distrust modern technology -- It works great when it works, but in a pinch trust the old tried and proven methods.
Ever see the white ones? Ever see their spectra? Well, the usual white LEDs are not perfect, but they are a good enough kind of "white" to improve upon "cool white" fluorescents in terms of color rendering index!
There are now some that I see as defeating such a claim! Such as most and maybe all Pelican "Recoil" models, and for that matter a large majority of units having a single LED rated at least "1 watt"? Even the Dorcy brand ones I have seen at Target with "1-watt" LEDs? And almost all others that rightfully say that the LED is a "Luxeon" one even if they do not mention wattage?
That has not been my experience!
Drop it when it is on and the bulb has some fair chance of getting killed as dead as bugs die in Raid commercials!
Same for Mag lights with incandescent bulbs, even though the rest of the flashlight can probably survive getting over by an 18-wheeler!
They are now making mantles non-radioactive (and slightly inferior to the old ones that were/are only mildly radioactive). Meanwhile, I have on hand enough batteries, LEDs, resistors, flashlights (mostly LED ones), to not be wanting for light! Just try putting almost any Pelican LED model, any model with a "Luxeon" or any other LED at least
1 watt or even a Lightwave 3000 butt-first into a coffee mug to make a nice illuminating spot on the ceiling! It is a step below a gas mantle lamp with a propane tank, but what will be reasonably purchasable to put in every room that has high cance of desiring light when a bad power failure hits?
An advantage of LED flashlights is that most tend to go into "energy conservation mode" when the batteries weaken - especially if the batteries are disposable alkalines! When a propane tank gets depleted, it is depleted! And incandescent lamps have efficiency decreasing greatly when underpowered, and I find this to be the biggest reason why LED flashlights (and bicycle lights) can claim so much longer battery runtime!
I am considering the LED flashlights that have proven themselves to be in the cream at the top or close to that to have adequately proven their superiority over incandescent ones. Mainly, when batteries weaken, at half of full current an incandescent flashlight "lamp" ("bulb") is dimmed to in or almost in "cigarette glow" category, while LEDs do not lose efficiency that badly when underpowered. Heck, most white LEDs have a slight gain in efficiency from mild, moderate and moderately severe underpowering! Give a white LED 20% of rated current, and look forward to often somewhere around 22% of "full" light output! Give your favorite krypton-filled incandescent flashlight lamp 20% of "full normal" current, and expect light output to be somewhere between "dim side of idling cigarette" and that of a cockroach that has endured (but not survived) a "Raid" commercial!
Don, your excellent points are duly noted, but my original question remains valid. Which slightly modified reads, given that there of tense of millions of 2 D-cell flashights as a market, why are conventional PR-2 bulbs no longer generally available, while the batteries themselves readily are?
I suspect that the reason is three-fold. First, the PR-2 bulbs worked very well and lasted a long time (unless dropped while burning) -- I would guess based on my experience 8-10 years as an average. Second, compared to a Krypton bulb, PR-2 bulbs are incredibly cheap when available -- Krypton bulbs are expensive (and based again on my personal experience) don't last very long. (I've tossed out 3 Krypton flashlights because both the flashlights and their bulbs turned out to be total crap and unreliable, while like the Energizer Bunny the old Rayovac contractor' model flashlight keep going and going! That's why all contractors who require a reliable and rugged flashlight keep using them). Thirdly, newer is not always better -- This is why contractors, utility meter readers, and others who need a reliable flashlight stick to the tried and proven old reliables, which mostly use PR-2 bulbs -- on in the case of 6-volt lanterns the PR-13 version.
Ask any old design engineer and he/she will likely share with you two saying, first "Better is the enemy of good." Second, "If it ain't broke, don't fix it!"
In a flashlight, reliability and dependability is far more important that state-of-the-art performance!
D> > >John posted: "Isn't that the century old device that we replace with an
I may be a technology geek, but I also believe in"tried and proven" backups. Coleman dual mantle lantern and a two burner stove (left from the days of camping with our kids 20+ years ago). Kerosene heater in the basement and about two days worth of fuel stored outside. The house has two "real" fireplaces (firebrick & masonry, 4 foot wide firebox). There's wood for a week or so out under a tarp. My wife has a collection of kerosene lamps - all in secure places with some fuel in them
The freezer has a couple of gallon jugs filled with (now frozen) water, providing an instant 8lbs each of ice for the refrigerator and eventual water for drinking.
After a couple of days off the grid, I'll probably power an automotive alternator from one of the gasoline-powered yard tools to get power to charge the laptop battery, the battery for the UPS the keeps the network up, and the cell phone...