Extreme run time incandescents, cold war era.

Wondering if anyone else is interested in this sort of thing.
During the cold war, but before the LED age, there was a limited demand for flashlights, lanterns and area lights with extreme run times. The main application was for fall out shelters and the like.
It was a fairly common requirement to provide minimal battery lighting 24/7 for 2 weeks or more. Replacement batteries could of course be stocked and used but a very long run time per battery was called for.
In familiar surroundings an astonishingly low lighting level was sufficient for safe movement.

In most cases these lighting instruments were not specifically produced for the purpose, but were standard products fitted with a different bulb or sometimes a different battery. In many cases, bulb life was sacrificed in the interests of getting the most light from less than one watt of battery power.
Bulbs were very cheap, keep forever and take up little storage space. Stocking a hundred bulbs was trivial, 100 large batteries less so.

I have a few such relics stored away, regret no pictures, but there is not much to look at in most cases.

One example would be a standard 3D flashlight that was fitted with 2 cells each F size and a 2.5 volt 0.15 amp bulb. That would give about 50 hours service. The bulb would be a bit over run and would need replacing each time the batteries were changed, and perhaps sooner.

Another example would be any common type of light that used a pair of 6 volt lantern batteries and a 0.5 amp PR base bulb. Replace the supplied bulb with a 5 volt 0.09 amp bulb for a run time of about 200 hours. Several bulbs would be needed in that time.

Area lights were usually home made to suit the application. Often consisted of a 6 volt screw terminal lantern battery connected to one or more miniature screw base bulb holders. The greatest run time would be a 6 volt 0.04 amp bulb for a run time of several hundred hours. A much brighter light could be obtained from a series pair of 2.5 volt 0.2 amp bulbs, but the run time would be less than 100 hours.

Another option for area lighting was a suitable number of large 1.5 volt cells in series, known as "flag cells" in the UK. Four of those and a 5.5volt 0.3amp bulb give a bright light, sufficient to read by, for at least 100 hours.

All the run times given refer to zinc carbon cells or batteries, alkaline not in general use at that time.

Fascinating stuff, thanks for sharing.

I'm one of the rare low lumen, night vision, runtime nuts on CPF and enjoy collecting and testing efficient moonlight/low lumen lights (lightbox, ammeter, and side-by-side runtime tests). I personally use 0.3 and 3 lumens ~ 45/45% of the time (course all modern LEDs), and don't really care much about the higher modes - they're more just for fun for me and see minimal use. The greatest "free" power source for lighting is merely allowing your eyes to dark-adapt, combined with an efficient light with good low low modes to take advantage of that. Had I been a flashaholic during that era, I'm certain I'd be after the examples you site.

I'm amazed at how much efficiency has advanced... your examples of "greatest runtime" seems to be (if my math is correct) ~0.24 watts and "sufficient to read by" is ~1.65w. My sweet spot for reading (course beam focus counts) happens to be a regulated ~0.3 lms which draws ~0.015w (11ma/1.3v or 4ma/4v). That's ~250 hrs from a AA alkaline.... or ~2.5 months from a D cell .

Once again, thank you for sharing that - I found it very interesting .

Very interesting stuff, guys. Not the sort of thing I would collect but fun to read about.

Very cool stuff, broadgage. I would be interested in seeing some of this IF it's NO trouble to you sometime down the road (please don't go to any trouble on my account!).

Edit: I figured out the question I asked in this space

reppans said:

Fascinating stuff, thanks for sharing.

I'm one of the rare low lumen, night vision, runtime nuts on CPF and enjoy collecting and testing efficient moonlight/low lumen lights (lightbox, ammeter, and side-by-side runtime tests). I personally use 0.3 and 3 lumens ~ 45/45% of the time (course all modern LEDs), and don't really care much about the higher modes - they're more just for fun for me and see minimal use. The greatest "free" power source for lighting is merely allowing your eyes to dark-adapt, combined with an efficient light with good low low modes to take advantage of that. Had I been a flashaholic during that era, I'm certain I'd be after the examples you site.

I'm amazed at how much efficiency has advanced... your examples of "greatest runtime" seems to be (if my math is correct) ~0.24 watts and "sufficient to read by" is ~1.65w. My sweet spot for reading (course beam focus counts) happens to be a regulated ~0.3 lms which draws ~0.015w (11ma/1.3v or 4ma/4v). That's ~250 hrs from a AA alkaline.... or ~2.5 months from a D cell .

Once again, thank you for sharing that - I found it very interesting .

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Very cool stuff, reppans; you're potentially making a convert here...

A number of years I came across a neat little PR-base bulb that was still reasonably efficient, and a very good match for 4xNiMH:

4.7V, 0.375A = ~2 watts

Bringing new life into a old Mag 3D, with low & high **Beamshots**

I estimated the bulb output at ~50 lumens or so, and calculated runtimes from 4xC alkalines to be ~18 hrs.
So something like ~27 hours from 4xD's, not too shabby while still retaining a good color temperature.

(Please forgive some details of the thread as I was a bit of a newb at the time. )

BTW, I'm moving this thread to the general /Incandescent/ subforum as I think it has broader interest there.

Really interesting read. I'd love to see what one of those bulbs look like if you have time to snap and upload a couple pics to tinypic.

I don't know how many remember, but Surefire used to sell a 'Hurricane Light', a kind of vampire light for used CR123 cells. When there wasn't enough left in the cells to drive the P60 (or whatever incan you were using) one would put new cells in the main light, and put the used ones in the hurricane light. It had room for eight pairs of cells, and eight positions for a small pr base bulb that would use one pair at a time. It was designed to be an area light just bright enough to make one's way around, and really squeezed the last few ergs out of the cells. I still have it, but since I don't use primaries anymore, it is more of a novelty item for me now.

StudFreeman said:

Really interesting read. I'd love to see what one of those bulbs look like if you have time to snap and upload a couple pics to tinypic.

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don't have the means to upload pictures, but there is not much to look at really. A 5 volt 0.09 amp bulb looks pretty similar to a higher current bulb. The filament is much thinner of course but this does not show well on a photo.

Most of the low current bulbs are, I suspect no longer manufactured, but a lot of NOS exist and they turn up regularly on fleabay.

PR 5 volt 0.09 amp not readily available
PR 3.8 volt 0.3 amp, still made

Most of the low power miniature screw base lamps are still available, though I suspect no longer manufactured. Note that some types are intended as indicators and need to be over run to give a reasonable light output.
6 volt 0.04 amp are better run on 5 cells than on 4 cells

Very high capacity disposable batteries are still manufactured, I think that the largest size is 2,400 AH and no that is not a typo ! two thousand and four hundred ampere hours.
Such a cell would light a low current 1.5 volt bulb for a year continually. A few dozen spare bulbs would be needed though.

I hate to bring up an old thread but ive seen these on ebay between 100-150 usdwhile searching other items. Always wanted to hear a little background on it. Thanks for the good read!

In the late 90's a winter ice storm knocked out power in my all electric home. Well millions were without power and I was remote, which meant way down the list of importance.

I discovered low power flashlights were a good thing. But I used mainly jar candles.

Yet in a cold war era the thought was nuclear fallout, so the last thing you wanted to do was light your space with things that were robbing your oxygen available.

I gave that some thought during those 17 powerless nights with temps that caused me to place my food in coolers outside as that was better than the non functioning refigerator/freezer.

When the power returned I went to stores and stockpiled jar candles, low power aa and aaa lanterns and thanked my lucky stars to have power again.

I still have many of those candles and lanterns stashed and have numerous low powered devices at numerous locations in my day to day areas of travel.

But now that Ima flashaholic, this thread intrigues me into thinking cold war era lights would be a great direction to turn, and displaying them would make sense.

I have found a source of an old type of low consumption bulb.
2.5 volt, 0.06 amp. Miniature screw base/E10.
One of those and a couple of zinc carbon D cells should give a run time of about 100 hours, or over 300 hours on alkaline D cells.

Until I receive the bulbs I don't know if they are designed as flashlight bulbs or as pilot lamps.

If designed as flashlight bulbs they should give an acceptable light for dark adapted eyes in familiar surroundings, but probably only last a few or a few dozen hours. The batteries might outlast the bulb.
If designed as pilot lamps, then the output will be even dimmer but they should last hundreds or thousands of hours.

I can give supplier details, they are in the UK but airmail should be affordable for such small items.

Timothybil said:

I don't know how many remember, but Surefire used to sell a 'Hurricane Light', a kind of vampire light for used CR123 cells. When there wasn't enough left in the cells to drive the P60 (or whatever incan you were using) one would put new cells in the main light, and put the used ones in the hurricane light. It had room for eight pairs of cells, and eight positions for a small pr base bulb that would use one pair at a time. It was designed to be an area light just bright enough to make one's way around, and really squeezed the last few ergs out of the cells. I still have it, but since I don't use primaries anymore, it is more of a novelty item for me now.

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Not certain if the Surefire "hurricane light" was ever really intended as a serious light source. It drained expensive lithium cells relatively quickly and gave a miserable light from a bulb that was a 2 pin type, not PR base IIRC.
At the time, surefire branded cells were made by a third party and a legal agreement prohibited Surefire from selling them below a certain price.
The hurricane lamp evaded this rule as it was a cheap plastic flashlight, COMPLETE WITH BATTERIES, rather than a sale of spare batteries.
The hurricane lamp, complete with batteries, sold for a lower price than a similar number of loose batteries.

I have now received a selection of old style low consumption miniature screw base bulbs, very low consumption in some cases.

2.5 volt, 0.06a-------surprisingly bright for the low current, should give many hours of service even on zinc carbon AA cells. Still in production, perhaps surprisingly.

3.8 volt 0.07a------entirely usable output, I fitted one in a cheap cold war era pocket lamp that uses 3 C cells, measured run time about 30 hours on zinc carbon C cells, these lamps also appear to be still in production. This is probably similar to the originally intended bulb.

8 volt, 0.05a, sold as cycle bulbs, but seems a very odd rating for a bicycle lamp.

broadgage said:

8 volt, 0.05a, sold as cycle bulbs, but seems a very odd rating for a bicycle lamp.

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Tail lamp bulbs, perhaps?