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

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ImA4Wheelr
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I figured you meant you removed the resister from the driver, which is what I first suggested in Post 13.  I was just childishly feeling unrecognized as I did spend a little bit of time looking into the driver to get that information.  But now, I see I left a zero off the resistance in my above post.  I should have said 4700 ohm resister.  The resister you removed from Bay R2 should have been marked "4701" which is 4700 ohms.

djozz
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ImA4Wheelr wrote:

I figured you meant you removed the resister from the driver, which is what I first suggested in Post 13.  I was just childishly feeling unrecognized as I did spend a little bit of time looking into the driver to get that information.  But now, I see I left a zero off the resistance in my above post.  I should have said 4700 ohm resister.  The resister you removed from Bay R2 should have been marked "4701" which is 4700 ohms.

Ah, I see it was not my language that was the reason for the post.

And I'm sorry ImA4Wheelr,  I am totally guilty of not recognizing you being the one to suggest the removing of R2 first (that was indeed marked 4701). The (bad) reason was when reading your post I was in the process of considering using a boost driver for AA, and so I did not read it very well. And when I was back on track with the lineair driver it was suggested again by gmarch. I will do better in the future, more carefully reading the suggestions people have for me Embarassed .

gmarsh
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I didn’t notice ImA4Wheelr’s suggestion earlier when I made the suggestion myself. 100% credit goes to him Smile

With the driver mounted in a pill, it should be much more manageable thermally. Also, most electronics parts will operate reliably at “second degree burn” temperatures – the Tiny13A and 7135s will happily run at 85C ambient according to their respective datasheets.

ImA4Wheelr
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No apology necessary.  Nice of you both for the respond how you did. I'm sorry for my over sensitive moment.

Please return back to this interesting build.  Looking forward to watching it progress.

djozz
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got a few more things done tonight.

The electrical set-up works, what about the host? Performance-wise I should go for the empty (brass) C8 pill I still have somewhere, throw it all in and watch the throw if I put it in the Uniquefire T20 with a A123 LiFePo battery. With the 90 degrees output of this led that should match very nicely. But I just don't want the led there, I want to extend my sk68 clone collection, so this will be the host:

The cheapest Banggood coloured clone, they managed again to use less aluminium, even thinner anodising, and the lens came thoroughly pre-scratched. But I must say, where it matters, it is still good: it has the silicone o-ring under the slider, zooming is smoother and it is a bit more waterproof than with the metal ring; although it has a hollow pill, it has a good edge for the led board to sit on; and last but not least, it has a screw-in led-board containment ring, I like that very much.

Now, the sk68-and-clones have a 14mm driver, the 105C is 17mm, so it will not fit in the driver opening. But there is enough room (18mm wide) under the pill before it narrows to AA size, and if i saw a bit off the pil I can let the driver float there, I have done that before.

    

But what about the heat? Normally I would not do anything about it and just wait for the driver to fry or not, but since I post about it here I thought it would be neat to make a driver heat-sink path.

This copper sock is nearly 17mm outer diameter, I used two slices of it for the heatsink. But first I had to shave a corner of two of the 7135 chips to make room for this copper ring (two out of eight chips of the 105C are mounted further to the edge than the rest). Can this be done without damaging the chip? Apparantly, because it did not lower the output current of the driver. I also replaced the short spring of the 105C for a even shorter brass piece:

a lot of sawing, sanding, fitting, soldering and filing later:

 

There is a small gap between the rings and the driver because the ring sits on top of the outer connections of the 7135 chips. It is 'tacked' in place by blobs of solder where the chips are (exept one, that I forgot). Had to use a small blowtorch to heat the copper to the melting temperature of the solder, while avoiding aiming the flame directly at the driver. Here is how the driver should fit inside the host, it will be screwed tight between the pill and the battery tube:

I soldered the wires to the led-board, but now I'm stuck because the Arctic adhesive that I need to glue the led board to the pill (which has to happen without making electrical contact between them, I hope that it will work!) is in the bedroom where my (disused) work bench is but also where my girl-friend is fast asleep at the moment (I need sleep too ).

First option for any progress will be sunday night.

gmarsh
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That last picture is awesome. What’d you use for a camera?

djozz
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gmarsh wrote:
That last picture is awesome. What'd you use for a camera?

Thanks, I like it too Smile

For posts here at BLF I always use my phone camera (at the moment a XperiaZ, it has a very ok camera). Phone camera's always do good close-ups because of the small diameter lens and sensor. I always pay some attention to the lighting of the subject and try to make the right cut-out, to make a picture look nice.

MRsDNF
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Amazing work djozz. I love your copper work.

 

djozz quotes, "it came with chinese lettering that is chinese to me".

                      "My man mousehole needs one too"

old4570 said "I'm not an expert , so don't suffer from any such technical restrictions".

Old-Lumens. Highly admired and cherished member of Budget Light Forum. 11.5.2011 - 20.12.16. RIP.

 

HBomb
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Awesome work so far!

djozz
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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 Undecided . 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 Laughing.

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).

 

ImA4Wheelr
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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.

gmarsh
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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.

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


Counterfeit 18650s, 2,<a href=“http://

bowhunter
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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???

djozz
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bowhunter wrote:
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???

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. 

bowhunter
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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” !!??

djozz
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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.

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