Dorcy Super 3 Watt LED Lantern

Check out the latest flashlight review:

http://www.flashlightreviews.com/reviews/dorcy_3wlantern.htm

As far as I know, this is the first 4D lantern style light that uses a high power LED. That large reflector produces incredible throw. It's a shame that this paricular model has such a puny overall output. I would like to see this lantern with either a Luxeon k2 or an Osram Ostar driven close to the limit. The head could be made of metal and there's plenty of space for a large heatsink.

It should be regulated too.

monkeyboy said:

The head could be made of metal and there's plenty of space for a large heatsink.

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It could be, but if I recall correctly, in stock form this Dorcy has a head made almost entirely of plastic. There's almost no thermal path for the Luxeon. The poor thing is surely doomed to cook itself to death.

I guess the typical owner should get at least a couple hundred hours of life out of the thing, if not a thousand. That's still better than most incandescent lamps. By then, LEDs will be even brighter and more efficient. You can throw it out and buy a better one.

For a Luxeon 3, I think an internal heatsink would do the job like in the SL 4AA luxeon. The head is so big that a large heatsink could dissipate enough energy into the plastic. The existing luxeon 3 could then be driven 3 times brighter which would make it out throw just about anything.

I think this lantern would be good for modding.

I modified and sold a few like this over a year ago now and still no problem. I took a regular $3 lantern and modified the reflector a bit for proper focus. I used a 1/4" thick slug of aluminum about the diameter of the reflector as the heat sink and a resistor to bring the voltage down to about 4 volts. No problems and throws a baseball beam about forever.

Since it will run on 4 'D' batteries, I wonder how the runtime would be using NiMh AA cells inside 'D' adapters?

Got one of these at a Sear's hardware on sale for $30 a while back. Doug's not kidding about beam being ringy. I pulled the head apart and sputtered the reflector, and now it is much better. Still has just one darkish ring outside the hotspot, but no big deal off the white wall, and still seems to have almost all of the throw the smooth reflector had. I am surprised at the "low output" remarks, as mine seems a real killer. Blows away my small 3W lights. The closest thing I have to it is my Dorcy 3-D 1W, but that is a real small hotspot, this thing throws a bigger spot out there, so I would have guessed it makes more overall light. Looks like my eyeball assesment is contrary to the numbers on the reviews. :shrug:

I guess it's possible that the manufacturer made different batches using different resistor values for the voltage regulation. Perhaps the first batches were brighter but people complained about LED's burning out so they increased the resistor value.

Hondo, does this use a visible resistor that can be easily replaced by a lower value one or a more sophisticated voltage regulator?

How easy do you think it would be to add a heatsink?

As I recall, it is just a direct drive through a resistor. Not sure about packaging a heat sink, I would have to open it up and have another look. If I do I will try to read the resistor value. My subjective impression may be influenced largely by the effects of a nice, big reflector at work.

Its odd, whoever the engineer is obviously never used a luxIII.

If its driven at full power it will , but this is driven at a Lux I supposely for greater efficiency.

Doug ran this for 42 hours, im surprised it didnt , I tested my XO for 2 hours and the aluminum was very warm to the touch, after 3 hours I dropped it upon picking it up.

It would be better if the reflector was trimmed, enough to install three luxeon I's and gives a space for a large heatsink

Yeah, I agree with Hondo too. I bought one of these things not too long ago and this thing is quite a thrower itself. It blows away all of my 3W flashlights. I honestly like this lantern a lot, except for the beam that is...

OK, in the name of science, I took my light apart again (not that tough). It is direct drive with a resistor. The resistor in mine is 2.2 ohms. The plastic base for the star looks like if one could duplicate it from aluminum, or better yet copper, would be a good sink for heat, were one so inclined.

Great Idea, to much plastic for my liking

Thanks for the information Hondo

If I had the time, I could try fitting a heat sink and replacing that 2.2 ohm resistor with a variable resistor. I would gradually turn down the resistance until the LED blows. Then I could buy a new one and rebuild it with a slightly higher resistance value.

monkeyboy said:

Thanks for the information Hondo

If I had the time, I could try fitting a heat sink and replacing that 2.2 ohm resistor with a variable resistor. I would gradually turn down the resistance until the LED blows. Then I could buy a new one and rebuild it with a slightly higher resistance value.

Click to expand...

That's exactly how we build model airplanes for maximum spin. Keep cutting down the vertical stabilizer for more spin until it won't come out of the spin. Then when you rebuild the plane, make it a quarter inch longer than that!

Hondo said:

OK, in the name of science, I took my light apart again (not that tough). It is direct drive with a resistor. The resistor in mine is 2.2 ohms. The plastic base for the star looks like if one could duplicate it from aluminum, or better yet copper, would be a good sink for heat, were one so inclined.

Click to expand...

2.2 ohms? I dont recall a resister that registers 2.2 ohms...

is it a combination of resistors?

Im thinking of modding my 4D eveready lanturn into a Lux III using the same circuit schemetic as the dorcy

Illum_the_nation said:

2.2 ohms? I dont recall a resister that registers 2.2 ohms...

is it a combination of resistors?

Click to expand...

Just one resistor, red-red-gold-gold. According to my Captain America resistor decoder ring, that is 22 divided by ten, or 2.2. No idea where OEM's get that sort of thing, but it seems to be out there.

Hondo said:

Just one resistor, red-red-gold-gold. According to my Captain America resistor decoder ring, that is 22 divided by ten, or 2.2. No idea where OEM's get that sort of thing, but it seems to be out there.

Click to expand...

best I can get is 2.5 ohms...thats 4 10 ohm resistors in parallel

If you are looking at Radio Shack for resistors to mod the lantern (sneak back on topic) to more or less brightness, I recall more "odd" resistances like this being included in the jumbo assortment pack. I used two tens to get five in my Fenix because, like many, I did not need 100+ various resistors.

Hondo said:

If you are looking at Radio Shack for resistors to mod the lantern (sneak back on topic) to more or less brightness, I recall more "odd" resistances like this being included in the jumbo assortment pack. I used two tens to get five in my Fenix because, like many, I did not need 100+ various resistors.

Click to expand...

Well [reflecting this topic] I was going to mod my 6V eveready lanturn into something like this...

It'll be a waste to but a jumbo pack and use just one...
Sorry, off topic, back on topic:

if the relector of the dorcy 3w is slightly marred in a ring by 500 sandpaper, would it soften the beam?

Ugh, yeah, the stock beam is a mess of artifacts. As I mentioned earlier, I sputtered mine with clear Krylon. Scuffing it sure would soften the beam, but I am betting the losses would be pretty significant. Some say the sputtering technique is lossy, but I am with those who maintain it just appears that way because light is diverted from dead center to the spill, and total output is not affected that much. A search on "sputtering" should yield several explanations of this, my attempt and others are in this thread:

https://www.candlepowerforums.com/threads/97000

When I was done, I still had one darker, but even, ring outside the hotspot, everything else was nice and smooth. Much better, and still throws a mile.