7135 based driver on LiFePo battery? (=also IR light build thread, with measurements on Oslon Black 850nm led, mod finished now)

Flashlight Modding and DIY Parts
41

I finished the light today.

I found the Arctic Alumina adhesive, and used it to glue down the led board. AA-adhesive is not electrically conductive and I needed the board insulated from the pill because the thermal pad of the led is not electrically neutral but connected to the led+ . It was the first time I used this stuff and learned a lot and it almost killed the light. It is frightening stuff actually, you mix component A and B and then you have 5 minutes before is hardened out. Applying it already took a few minutes, then the board was pushed in place and then I screwed down the metal ring over the board (with a plastic spacer in between ring and board) to push it tight against the pill, I should not have done that: I tested the light and it did not switch on, the led board touched the pill, probably at the side. So I had to remove the ring again, but at that point the adhesive was almost fully hardened out. It took all the force and control I had at the same time to get the ring back out (man, that adhesive sticks very well indeed), and just in time I could shift the led-board a bit with a small screwdriver forced in at the side of the led-board to remove the short and have a working light (there was no way I would have ever got the board out again, half a minute later and I don't know what I could have done) .

Here's a picture of the applied AA-adhesive before it hardened (after all I should not have taken the picture, it costed valuable time):

And here's the salvaged pill inside the light:

Finished:

And then it felt rather strange: I have a finished mod, it turns on, it draws a steady 2.74 amps at almost 2V (5W), and it warms up quickly so it is all quite well done.......... but I can't see the light . A faint red glow, but nothing more. I turned on my phone camera, but it has a IR filter so although it shows something vague at 1 meter and even at 4 meter, it's not anywhere what I want to see out of a 5W pocket thrower.

So now I need a proper IR-camera to test and make use of this flashlight. Should have thought of that before I started it .

Here are the phone camera shots anyway:

control shot at 1 meter, zoom out at 1 meter, zoom in at 1 meter (it is not pitch dark, a small desk lamp at the very other side of the room is switched on).

And a shot zoomed in from 4 meters away:

So I did this for fun, just because I was able to buy a few Oslon leds including this IR one. And I hope to find a cheap camera without a IR-filter (or mod one) to have some more fun. But my question is now: what can you actually do with a 850nm sk68 clone? (no, for a TVBgone light you need 950nm). I guess there will be hunters who use these kind of lights (I guess this particular mod does not withstand the recoil very well). But is there anything else?

I have collected quite a line-up of sk68 clones thusfar (the left one is stock).

42

Looks great. Nice save on moving the emitter base in that short curing window.

Some day when I find a decent, affordable, IR goggles (or camera, etc), I want build one of these too. I'm wondering if one can spot things that are deeper in my woods at night with such a set up. Sometimes my dogs growl and bark like crazy but don't pursue. I'm curious what they are sensing.

Please up date this thread when you do try this light out with IR equipment. I hope people see your question in the above post. I'm curious too.

43

Yeah, I probably should have described the process for using Arctic Alumina a bit more. But hey, it’s done - and the star’s secure.

Get your hands on a cheap used point’n’shoot digital camera, carefully disassemble it and take the IR filter out. I’ll warn that It’ll completely ruin the camera for taking regular pictures.

44

You can attach an IR filter on the front for regular pictures.

45

DJOZZ

  • was it the osram olson 4715s led that you used in this build?

- how has the led held up with the high amps you are using - well over 2 amps???

46

Yes, it was the 4715s led. I have not used the light since the build actually. I was going to use it together with a videocamera with IR-filter removed, but I did not get the camera to work properly, and then I stopped working on it. Sorry about that.

But the test I did showed a maximum output of this emitter (on a copper board) at 5A, so I am not too worried about failure at 2.8A.

47

Correct me if I am wrong but is the olson IR 4715s rated at a max of 1 amp?

if so - you have it very overdriven!

when you did your tests were you able to tell if light output went up considerably as the amps went up??

I also want to drive this same emitter off a a123 lifepo4 cell so am interested in how the driver/light worked with the low voltage protection “zapped” !!??

48

I know it is rated for 1A, but the official rating is usually not based on the led mounted on a copper board like I did, the experience is that you can go higher on copper. I did a test first before deciding on 2.8A, it is at the end of post #18, it shows that the output is still rising sharp at that current.