Need advice on replacing old incandescent bulb with an LED

wosser

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I have recently acquired a vintage flashlight and I would like to convert it to use an LED.

Unfortunately I don't know anything about incandescent bulbs or their mounting hardware and I was hoping someone help me to identify a suitable LED.


  • Text on the metal barrel: "3.5V0.26".
  • Glass envelope diameter: 10.9mm (0.43")
  • Metal barrel diameter: 9.3mm (0.37")
  • Total bulb length (glass to end contact): 22.5mm (0.89")
  • Screw-in type
  • Approx thread pitch: 1.83mm (14 TPI?)

The kind of LED I'm looking for:


  • Preferably a screw-in LED module that fits this thread type, but it's not a deal-breaker if it's another type.
  • Low-ish power, perhaps 300 lumens max output, mainly because heat management would be difficult at a higher output.
  • Very warm colour tint.
  • I'm planning to use a 1S2P 18650 pack with protection PCB to power the LED.
  • A wide floody type, maybe with a mild hotspot. Open to ideas on this.
  • Compatible with the existing reflector (1.3" diameter smooth metal).

The mounting bezel is push-fit into the reflector, so this mod I'm hoping to do will be non-destructive to this lovely old Svetlina flashlight (I've got another thread about that).
 
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xevious

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To get an LED in that light, you may have to do significant mods. There's a guy on CPF who is a bit of a specialist on this kind of thing. But... the cost may dissuade you. There are direct swap LED module-bulb replacements for incandescent bulbs, mostly for Maglites.

Check out these topics to see what others have done:
__ You Just Know You're a Flashaholic When... (some vintage conversions in this)
__ What's your oldest LED flashlight?
__ Photos of your lights

Unless this is a really rare and unusual vintage flashlight you want to keep using, I'd ditch the plans. You won't be happy with the result. And... for the cost and effort, you could find so much better value for your money in modern LED lights. If you're on a budget, there's a "budget light forum" you can check out that often features ongoing sales topics to find good deals.
 
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xevious

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That's kind of a bummer. Thanks though.
You may just consider your vintage flashlight to stay vintage... just keep as is, as a conversation piece or to use on occasion. I've done the incan-to-LED conversion on a Maglite and while it's a little better than the old bulb, it's still rather anemic when it comes to what's possible today in a whole new LED flashlight.

If you do enjoy that warm glow of incandescent, then look into the "tint game." Hi CRI (color rendering index). There are some LED emitters that produce astonishingly warm light that can fool some people into thinking it's incandescent.
 

xxo

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Wosser's "Svetlina" light posts got me interested in these military lights again (I have wanted one for some time) so I just ordered a similar light – a Swedish army "Ficklampa 3" and was going to post asking the same thing about LED drop-ins. It looks like the Swedish light uses a similar E10 screw based bulbs but it runs on 2 C cells instead of the traditional 3R12 4.5 Volt flat lantern battery.

I see that superbrightleds has a E10 based 1 Watt 1-9 Volt LED bulb that looks good, though it is currently out of stock/on back order.

There are also some 1 Watt E10 base LED's on amazon in 3V, 4.5V and 6V varieties, but I would rather have a 1-9V Voltage range like the superbright bulb if possible.

Does anyone have experience with the E10 based LED drop-ins?
 

ZMZ67

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I have been using them in some old style lights and have been happy so far. I had to search for years for suitable reverse polarity models for my railroad lanterns,finally came up with some dual polarity models on Amazon. That is where I have been finding E10 base LED drop-ins but I am guessing Ebay would be a source as well. Most drop-ins available seem to be positive polarity and the voltage range varies. There is a site in the UK that another member referred me too that carries the 1W dual polarity E10 base drop-ins,www.thetorchsite.co.uk but I never ordered from there directly. The dual-polarity drop-ins I bought through Amazon did ship from the UK so it could possibly be connected with the same site. Never tried any from Superbright though I have looked on their site as well.

To the OP,the output I see for these kind of drop-ins is no where close to 300 lumens. Usually low output 30-50 lumens or for the better ones 100-120 lumens.
 

wosser

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I think I've found the perfect LED for the job. However it does involve a lot of "no way back" mods. So I guess this light is no longer collectable. So be it, the red mist of flashaholism is upon me!
I've machined-up a heatsink shim out of brass and epoxy'd it to the inner back wall of the case. The LED I found is a 3 Watt COB, so the plan is to mount the LED on the brass and let the heat conduct to the steel case.

Not that there's heat much to deal with, the LED seems to settle at 60 Celcius (140 in Freedomheit) without a heatsink at (3.7 V, 480 mA, through a 1 Ohm, 1 Watt resistor). So the brass and steel should keep things nice and cool.

Found a nice 5200 mAh Li-Ion rechargeable with protection circuit which fits comfortably in the case with a bit of room for the Microcontroller / FET / PWM circuitry.

The beam from the LED ion its own is fairly typical of a COB, very even featureless spread over a very wide angle (135 degrees from centre) and a great warm tint that is fairly close to the original incandescent.
I'm hoping that once installed into the reflector, some of the "vintage" distortion and crustiness will be present in the beam pattern.
 

xxo

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I have been using them in some old style lights and have been happy so far. I had to search for years for suitable reverse polarity models for my railroad lanterns,finally came up with some dual polarity models on Amazon. That is where I have been finding E10 base LED drop-ins but I am guessing Ebay would be a source as well. Most drop-ins available seem to be positive polarity and the voltage range varies. There is a site in the UK that another member referred me too that carries the 1W dual polarity E10 base drop-ins,www.thetorchsite.co.uk but I never ordered from there directly. The dual-polarity drop-ins I bought through Amazon did ship from the UK so it could possibly be connected with the same site. Never tried any from Superbright though I have looked on their site as well.

To the OP,the output I see for these kind of drop-ins is no where close to 300 lumens. Usually low output 30-50 lumens or for the better ones 100-120 lumens.

Thanks much for the info.


Is this maybe the LED that you got?

https://www.amazon.com/dp/B01631XMUY/?tag=cpf0b6-20

....the description seems very similar to the one on the TTS site:

http://www.thetorchsite.co.uk/TTS-1_Watt_Cree_Petzl_Bulb.html

both are listed @ 1 Watt/120 lumens w/ Cree XP-G LEDs with a dual polarity 2-9V Voltage range.
 

xxo

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I think I've found the perfect LED for the job. However it does involve a lot of "no way back" mods. So I guess this light is no longer collectable. So be it, the red mist of flashaholism is upon me!
I've machined-up a heatsink shim out of brass and epoxy'd it to the inner back wall of the case. The LED I found is a 3 Watt COB, so the plan is to mount the LED on the brass and let the heat conduct to the steel case.

Not that there's heat much to deal with, the LED seems to settle at 60 Celcius (140 in Freedomheit) without a heatsink at (3.7 V, 480 mA, through a 1 Ohm, 1 Watt resistor). So the brass and steel should keep things nice and cool.

Found a nice 5200 mAh Li-Ion rechargeable with protection circuit which fits comfortably in the case with a bit of room for the Microcontroller / FET / PWM circuitry.

The beam from the LED ion its own is fairly typical of a COB, very even featureless spread over a very wide angle (135 degrees from centre) and a great warm tint that is fairly close to the original incandescent.
I'm hoping that once installed into the reflector, some of the "vintage" distortion and crustiness will be present in the beam pattern.

Sounds like a fun project!
 

wosser

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... I just ordered a similar light – a Swedish army "Ficklampa 3"...

If you like yours half as much as I like mine then you've made a good investment. The form factor is so full of potential for mods and modernisation. All the mods I'm making to mine will be internal only - the exterior will (I hope) appear entirely original. EDIT: *Sigh* apart from the LED itself being visible of course -- not much I can do about that. At least the colour gels will still work :)

Are you planning to mod yours? I'd love to see some photos if you get a chance.

Cheers.
 

xxo

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Aside from getting a LED drop-in and 3D printing a couple of spacers to run AA's, I think I will leave it stock. I might also 3D print a dummy cell and an adapter to also run single 14500's, CR123A's and 16340's, but that's about it.
Right now, I am impatiently waiting for it to arrive.



A few pics that I found on the net:

doRnDdM.png


MTeeQtE.jpg


sp2FPfw.jpg




And a brief YT vid showing how it works:

 

wosser

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@xxo:

Interesting video. That blackout shade is just like what British cars had to use in WW2 during the Blitz. A metal cap went over the headlamps and prevented light from scattering upwards into the sky where roads could be traced by enemy aircraft flying overhead at night.

Personally I'd be tempted to replace that blackout slider with a yellow or blue gel filter. A blackout shade seems like a waste of lumens.

It looks like injection molded plastic construction, and quite decent quality (well it is Swedish right? :)). A leather strap and an orange peel reflector, nice. Let us know what you think of it.
 

xxo

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@xxo:

Interesting video. That blackout shade is just like what British cars had to use in WW2 during the Blitz. A metal cap went over the headlamps and prevented light from scattering upwards into the sky where roads could be traced by enemy aircraft flying overhead at night.

Personally I'd be tempted to replace that blackout slider with a yellow or blue gel filter. A blackout shade seems like a waste of lumens.

It looks like injection molded plastic construction, and quite decent quality (well it is Swedish right? :)). A leather strap and an orange peel reflector, nice. Let us know what you think of it.


The blackout feature looks kinda cool, better than the opaque blackout filter for the US MX991, I suppose? Seems like a lot of these lights have a blackout; some had a single slider for the blackout only, with no colored filters. In the US military back in the day we normally used the red filter most of the time for light discipline when reading maps and the like.

One thing that amazes me is that they stayed with the jacket button attachment for so long, I am sure a clip like on the US angle head lights, or at least the folding metal clip on your "Svetlina" would be so much better?

The plastic construction seems like a good idea to me, considering this light probably dates from some time after 1970? (just a guess, I don't know the history on these), should be nice and lightweight, quieter than metal when banged around and won't stick to your skin in extreme cold. I am sure the Swedes (not Swiss, but close enough? :shrug:) would use a good plastic that didn't get too brittle in the cold.

Probably the main reason I went with this light is that it runs on 2 C cells which makes it a lot easier to feed, at least in the USA, where 3R12 batteries are all but non-existent.
 

wosser

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The plastic construction seems like a good idea to me, considering this light probably dates from some time after 1970? (just a guess, I don't know the history on these)...

I am sure the Swedes (not Swiss, but close enough? :shrug:) would use a good plastic that didn't get too brittle in the cold.

Probably the main reason I went with this light is that it runs on 2 C cells which makes it a lot easier to feed, at least in the USA, where 3R12 batteries are all but non-existent.

Hehe, yeah I did write "Swiss" originally by mistake. Sweden also have a well-earned good reputation for making badass military kit too. When your unit arrives, take a few close-up shots of the hinges and the insides of the sliders - this might reveal clues regarding the approximate date of manufacture. The one in those pictures looks rather modern to me, given the sharp detail in the hinge bosses, the proud text (interesting in itself) and the slider channels. Other clues such as ejector marks and sprue marks might help too.
 
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wosser

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in the USA, where 3R12 batteries are all but non-existent.

I have been wondering about this since last week when I mentioned the Svetlina on this forum. Historically speaking, many technologies that were popular in WW2 Europe ended up being adopted by American forces and taken back to the US after the war and caught a foothold in the industrial market. Although the 4.5V battery was common in Europe, it perhaps was not popular! Perhaps Bykfixer has some perspective on this.

I know that the 4.5V batteries are still easily available in Eurasia, perhaps the Americans with their incredibly fertile industrial growth shortly after the war decided that they could do better.
 

xxo

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I have been wondering about this since last week when I mentioned the Svetlina on this forum. Historically speaking, many technologies that were popular in WW2 Europe ended up being adopted by American forces and taken back to the US after the war and caught a foothold in the industrial market. Although the 4.5V battery was common in Europe, it perhaps was not popular! Perhaps Bykfixer has some perspective on this.

I know that the 4.5V batteries are still easily available in Eurasia, perhaps the Americans with their incredibly fertile industrial growth shortly after the war decided that they could do better.

Yeah, I'm sure Bykfixer would know. From what little I know is that these 4.5V batteries were used to a limited extent from the early days of dry cell batteries up to about the start of world war 2 in the USA, but never seemed to have caught on in a big way.....it seems like Americans preferred cylindrical flashlights that ran on D or C cells or big 6V batteries for lanterns (I think the 6V lantern battery was never all that popular in Europe?). After the war much of Western Europe/NATO used a lot of US military gear, so the influence may have went more the other way, while Eastern Europe kept using their 3R12 battery powered lights?

When searching for info on LED drop-ins for this light, I saw that Petzl made a series of head lamps that ran on 3R12 batteries (and E10 based incan bulbs) until fairly recently, so I guess that the are people still using these batteries.
 
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