I have just bought a flashlight with OSRAM led (3x AA). I think it’s 3-4 Watt Golden Dragon warm white led if not mistaken. It is bright about 150-180 lumens I think.
What surprised me is that the led runs very cool even after running continuously for 30 min. I hardly detect any heat from the led. After 30 min, it is only very mildly warm around the head. My other AA flashlights with Cree led (like XPE or XPG 175-200 lumens) would have been very hot after 30 min.
First, I thought the heat was not transfered to the body of the flashlight, but I really don’t think that is the case.
Even the glass lens is cool to the touch. If the heat was there, at least the glass lens must have been hot since it is very close to the led.
Is it a fact that OSRAM led really run much cooler than Cree ?
Watts is watts… at the same power levels, it won’t run any cooler. If your flashlight seems cooler, it means the heat is not getting off the LED and onto the flashlight body where it can be shed yo the outside world … a very bad thing…
I’ve read somewhere that the OSRAM LEDs are designed to run cooler on the die than others due to their low thermal resistance between the die and pad.
I’m not sure if it’s any ‘better’ than CREE LEDs, but they make a big deal of it in the marketing materials.
Of course that has nothing to do with whether the outside of a flashlight runs cooler, it only impacts how cool the die runs and how long the LED itself lasts. If anything the outside of the flashlight would run hotter because the heat transfer to the outside would be better.
Completely unrelated, but I like the OSRAM diamond dragon LEDs very much. They’re not so great for flashlight use, but excellent for DIY light bulbs. I’m using 35 of them to build a garage lighting system (writeup to follow when I’m done). The LEDs are $1.33 on fasttech link though for that quantity they go even lower than the quoted 5+ price. An excellent deal IMO.
The only reason I bought it, because it is very cheap with interesting features. It’s only $7 new, and that includes factory’s 3x AA battery.
The seller modified the original flashlight with Osram led with Collimator lens & 5-mode driver (H, M, L, Strobe, SOS).
High is around 150-180 lumens, Med around 80-100 lms, Low around 20-30 lms, Strobe/SOS at High mode.
The seller claimed 3+ hours on High with Nimh (3x AA)
I have tested wit 3x AA Eneloop & I got around 3 1/2 hours with it. It seems to regulate quite well too. Not bad for $7 with such a long runtime.
The only thing I don’t realy like is the long shape & a little bit too warm for my liking.
This is the original unmodified flashlight :
” Completely unrelated, but I like the OSRAM diamond dragon LEDs very much. They’re not so great for flashlight use, but excellent for DIY light bulbs. I’m using 35 of them to build a garage lighting system (writeup to follow when I’m done). The LEDs are $1.33 on fasttech link though for that quantity they go even lower than the quoted 5+ price. An excellent deal IMO”
As soon as I can free up some time was looking at using the same LEDs for a shed lighting project also.
Love to see your writeup when you finish…
cheers,
Nic