nintendo64
Newly Enlightened
Would a plastic housing melt due to the heat generated by the LED? I was thinking of using a Smart krytonite or similar light and fit a LED inside, with external battery.
Will a LED melt a plastic case?
- Thread starter nintendo64
- Start date
Help Support Candle Power Flashlight Forum
PCC
Flashlight Enthusiast
That was a Coleman Cree XR-E 105 lumen headlamp that melted. The picture is of the back of the tiny heatsink and you can see the black plastic has melted and started to sag. I guess that the 4 AA NiMH cells were a little too much for this little light, eh? It was designed to run on 3 AAA alkalines. It was mounted to my helmet on a bike ride so it was getting plenty of cooling air flowing over the unit. Fortunately, I stopped to take off my jacket as I was sweating pretty badly and I noticed that the headlamp was warmer than I had ever felt so I turned it off and left it off until I got home. That's when I noticed that I had melted it.
doesn't surprise me that melted.... 3AAA alkalines cannot put out anywhere near the current a Cree can handle and 4AA is probably overdriving it from about 300-500ma to 1.0-1.5A I would guess if not more.
I would suggest you try 3AAs and consider checking that large resistor as to see if that limits the current and adjust that for an acceptable but not driving it too hard type of level ....
if you are not using AAAs.... try and get a block of aluminum to attach to that cree that extends into the AAA battery holder area drawing off more heat.
I would suggest you try 3AAs and consider checking that large resistor as to see if that limits the current and adjust that for an acceptable but not driving it too hard type of level ....
if you are not using AAAs.... try and get a block of aluminum to attach to that cree that extends into the AAA battery holder area drawing off more heat.
Last edited:
PCC
Flashlight Enthusiast
I have since taken this light completely apart and salvaged the parts from it. Even overdriven this little lamp only put out around 60-80 lumens and was just not bright enough for my purposes. I'm going to put that lamp into a different project with a proper driver supplying the power and proper heatsinking, too.
nintendo64
Newly Enlightened
im thinking of getting a drop in LED from DealExtreme, since the can handle a variety of voltages (probably use a 6 volt battery). it dont say how many lumens, mAH for some of the models does anyone know where i can find the exact specs, any recommendations?
dropin for what? I am sure if you search for dropin based upon a light model you could find someone talking about one in CPF somewhere.
PCC
Flashlight Enthusiast
Nope, the Cree came out of a brand new headlamp that was probably manufactured earlier this year. The output has a very yellow tint so it is definitely not a brighter bin. I don't think the LED would overheat instantly when the light is first turned on and I never noticed that the light dimmed in use other than when the batteries drained. The LED itself has no signs of heat damage on the emitter nor on the attached lens.
I meant older as in older binned.. just because something says cree in it doesn't mean the newer cree bins and don't ask me what order is the best I only know Q4,5 and R2 are currently the best not sure where the P bin and lower Q bins sort out.
