Heat sinking the Ultrafire UF-H2B

Flashlight Modding and DIY Parts
1

Hello everyone!

As mentioned in Mr. Admin's excellent review I was a little bit concerned about the heat sinking in this light. Running on Hi it did not get noticeably warm which I thought is not ideal and looking inside the head there was no real thermal path. With a 14500 tailcap draw in my sample was 0,44 A. I have no clue if this is enough to cause a thermal issue for the LED (comments welcome) but I like my lights to last, so I thought better safe than sorry. The solution was straight and simple, here we go:

Inside the head embedded in the omnipresent white silicone is a heatsink-like object.

Extracted. Not the most beautiful example of craftmanship. It did not make any contact to the body either.

There's not much room inside the head, but still room for improvement.

I simply filed a piece of aluminium to an appropriate size. The side facing the LED is 6x6 mm, length is 10,5 mm. The end facing the occiput of the light is slightly curved to match the inner contour of the body.

After tapering the side facing the LED a bit to avoid contact with the LED leads and fine adjusting the length I could insert the new heatsink. I thought I would fixate it with thermal adhesive after the fitting, but it has such a tight fit that I could not extract it again, so I left it.

Before reassembling the switch I placed a piece of adhesive tape on top of the heatsink to avoid contact issues (the original soldering points of the leads to the switch are quite near the centre).

Now, I still don't know if this was necessary at all, but running on Hi the head of the light is now getting more than hand warm after a few minutes and I take it as a good sign having done this. :beer:

2

Great job! you can teach workers at the UF factory

I hope it all stay in place and that it will not short at the led

I have ordered thermal glue for exactly the same project (will also swap the led for a warmer one)

3

Thanks for this - I must pull off the switch off my H3 and see how it is for heat removal from the LED. All that thermal goop is not pretty at all.

4

And it's possibly better insulating than heatsinking. :D

5

Nicely done, Huny74! At 440ma draw off the battery I would guess that even the sloppy factory job may be adequate...but you've definitely improved on that, and should add a measure of reliability. Nice pictures too!

6

Thank you for the heads up! Im glad you tore yours apart to have a look. My UF-H2B came with the exact same type of crappy undersized chip of scrap aluminum - that didnt make contact from the emitter to the body. I'll be digging it out to fab a piece of copper to fill the gap within the next few days.

Its amazing that this light was initially so well crafted and then later completed by a monkey on crack. Either way, its a great catch on your part. Thanks again.

7

I did look into mine and it seems realtively bad, but can work. I'll leave mine as is for now.