Craftsman Variable Voltage Led fails catastrophically.

Hello All,
I have been lurking around here for couple of years now and have enjoyed all the information people pass around. Thank you all.

Well anyway this is what happened. I received one of those Craftsman Variable voltage pr replacement leds for Christmas. I put it in a 4d Dorcy like lantern that I bought at Walmart last year. I took out the Krypton bulb and inserted the Led. Turned it on everything seemed fine about what I expected in brightness. No big deal to be sure but it could be very useful.
Wouldn't you know it on New Years day we had a ice storm. Out came the lantern. I don't know how long it lasted but after maybe 15 minutes I did notice it was out. That was strange but I thought it was one in a million. I got back to sears today and got another one as a replacement. I came home and put it in and turned it on. I thought maybe this one was about the same as the first one but decided to leave it on for a while to see what would happen. This also went out in less than a half hour but this was different. I noticed I couldn't slide the on/off/focus switch. There was that burnt plastic smell to it. I unscrewed the lense and the reflector had been pushed up by the melting plastic below it and the socket the lamp was in had pushed up and melted over. I'm guessing that the only reason it stopped making heat was because the circuit broke because it moved so far. I haven't forced it apart yet because I wanted to take pictures so I could send them in to Sears and see what they say. I'm not sure what happened but could this be a case of reverse polarity?

Thanks again for your help.

:welcome:

Sounds like an over voltage/current problem. The lantern is probably direct driving the LED. I'm just guesing though.

Welcome aboard

Bill

if it was reverse polarity i doubt it would work at all... are you sure the drop-in supports 6v?

Was it this Dorcy lantern, or something else that just looks similar? Rayovac and Ozark Trail make very similar ones, but with reverse polarity.

I have at least 4 of the dropins and have had no issues with 2-4 cells with them. Although they do get uncomfortably warm on 4 cells, and I haven't done any extended runtimes on 4D with it.

It looks almost exactly like the Dorcy. It doesn't have the second metal support handle. It is walmart part #41-1021. I am going to pull it apart and see what I can fiqure out.
Thanks

I pulled the reflector off the lamp socket and saw that the spring on top of battery (The last negative connection before the lamp) and the thin wire to the negative contact on the lamp socket had melted throught the plastic on the lantern. I had to use pliers to get the lamp holder off and a screwdriver to pry the lamp out of the socket. I tried the lamp in two other lights. It's dead as a door nail. I checked all 4 battery and they test out at 1.48 volts each. I know sears will give me a new lamp and I'm out only 5 bucks for lantern. The good news now I need to buy a new lantern. I would still like to know why it fried though.

A brand of the lantern would help....

The Dorcy is the same price, and has the correct polarity.

I do have a led pr drop in I bought several years for a 3D mg. It operates at 4.5 volts only so I used a dummy cell in the lantern. I never used it for a long period of time and it just seemed so dim that I wanted something brighter and put the krypton bulb back in and pulled out the dummy cell.

I am quite sure the polarity wasn't reversed.

The biggest difference between this and the Dorcy above is on the slide focus control instead of saying Dorcy this has a couple of pyramid like symbols over lapping.

Steamer said:

I do have a led pr drop in I bought several years for a 3D mg. It operates at 4.5 volts only so I used a dummy cell in the lantern. I never used it for a long period of time and it just seemed so dim that I wanted something brighter and put the krypton bulb back in and pulled out the dummy cell.

I am quite sure the polarity wasn't reversed.

The biggest difference between this and the Dorcy above is on the slide focus control instead of saying Dorcy this has a couple of pyramid like symbols over lapping.

Click to expand...

Sounds reverse polarity to me. PR dropins in reverse polarity will often light dimmy, and then die.

You can know for sure with a DMM

I gave it a good look over and decided the polarity was correct. I was unable to get a reading on the dmm because the thin wire from the last battery spring to the small buss like bar that is connected to the slide switch had melted into the plastic and no longer makes contact.
I find it impossible to beleive that I got two bad lamps in a row. It has to be something with the lantern design. I couldv'e have had the batterys in backwards but the design makes it very hard to get away with that because of indentations on the positive connections.
When I first turned it on it appeared to be not quite as bright as a mag led.
The spring from the last battery and the 1 inch to the slide switch are the items that got the hottest and melted clean through the plastic housing.

I don't want to even suggest that the wire was to thin and thats why it over heated. The wire is thin but not that thin.

I dont know if this is relevant at all... or if the lantern mentioned in the comments below is the same as yours, but I came across it in another thread...

https://www.candlepowerforums.com/posts/2209135&postcount=19

Heres another comment on LED mods for 6V lanterns.
https://www.candlepowerforums.com/posts/2215798&postcount=39

You're not the first one to have it blow up at 4.7v.

Hi Steamer - a bit of envy here for your Craftsman led problem.

Would making a custom heatsink for the led help? Suck heat away from it?

Consider cutting an inch of copper pipe, then slit it open so you'll
have a rectangle of copper.
Then drill a hole in it that the led would fit snug into.
Bend it to contour to the inner side of the reflector? epoxy to make it stay?
add a little heatsink goop to ensure heat transfer...
\- just thinking...

Well thanks to everybody for the helpful links. I think I will assume that the something failed inside the lamp failed and created a direct short and that caused the spring and the connecting wire to the lamp holder to turn into a heater and melt. It just can't handle 6 volts.:thumbsdow I will be taking back the craftsman lamp and buy something else.

I had the same thing.Returned it,they had no more to try,cool thing was it went from 3 to 6 v according to package.