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ArcticMyst Security by Avery

Heat Produced by FlexDrive?

Wolfman29

Wolfman29

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Hey everyone.

Despite my build record, I have never used a FlexDrive before... and the build I am working on right now is the first one.

Now, I have it all set up to output around 413mA (for an LPC), and I have heatsinked the six-pin chip like is usually advised (used a small piece of copper). But, in order to prevent shorts, I wrapped it in electrical tape.

I am planning on using this laser with no duty cycles... at this current (using a 14500 cell for input), will the driver EVER overheat?
 





Wolfman29

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I do not. But that shouldn't be a problem. Point is, even if it is both electrically and thermally insulated by electrical tape (I mean completely covered), will it be able to have an unlimited duty cycle at 413mA?
 
Wolfman29

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I was thinking of doing that, but I honestly don't have the room in this host for that :\
 
DTR

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I have one of those around here somewhere. I will try to dig it up and see what I can think of. Is there enough room to cut a 4mm wide strip of say a penny and bend the edges up to sink to the walls of the pill? Similar to the ehgemus mod.:thinking:

p1012354.jpg


p1012643.jpg
 
Wolfman29

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Well, the thing is, with the heatsink I machined for it, the pill is about 7mm deep and about 15mm across. And some of that space is being taken up the battery contact. I *think* it should be fine running for that amount of time (and actually, I may test it...), because I don't expect to get longer than 60 minutes of run time.

EDIT: Yeah, so I just did some math... it shouldn't have to dissipate more than 150mW of power, which is like nothing, especially for something that size. It should be fine.
 
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Wolfman29

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I figure that I will be pumping out something like 300mA or so of current, and with a crappy 14500, I figure I should be able to pump that out for an hour or so. Maybe more?
 
Tonga

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I did a build with a Tank007 E3 with over twice the current also with a copper sink for the V5. I covered it with electrical tape and it showed signs of over heating with beam degredation. I had to take it back apart remove the tape and re-heat sink it with my copper plate ( cut just to fit and contact the pill with arctic silver). I covered the areas that the V5 could contact with liquid electrical tape. After this it works just fine. Thats just my dealing with tape. You are at a lot lower current but its the "no duty cycle" that's the big question.
The battery in my build is the AW 14500 750 mAhr. Fires at 975mW on my LPM.
 
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Wolfman29

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I just don't like the idea of risking a short and blowing the driver OR the diode.
 
Tonga

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Yeah, I know what you mean. The Liquid electrical tape is what I use now on all of my builds, for insulation works great! Good luck man;)!
 
RA_pierce

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Don't worry about the driver in this build.
I have used the FlexDrive in many pen style lasers including the LPC at ~450mA and heat-sinking for the driver is not necessary even in a host with minimal mass.
Dr.Lava states in the manual that heat-sinking is not needed when the FlexDrive is operated at <1000mA.
As long as you keep the diode cool enough I think you should not have any problems. Also, it may be worth noting that red diodes do not produce nearly as much heat as blue and violet diodes due to their lower voltage requirement (~2.5V compared to ~4.5-6V).

V x A = W = Heat + Light output
Subtract the wattage of light output to get you the approximate amount of heat generated by your laser diode in Watts.
 
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