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FrozenGate by Avery

How much heatsink?

ColdWelder

ColdWelder

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If I run a 445 at 275ma's, putting out about ~75mw, how much heatsink would i need to give it a continuous duty cycle?
 





try it out and see if it even needs it. If it does need heat sinking it couldn't be much.
 
Well, look at it this way: you are giving it 275mA, and it's putting out 75mW of light. It's probably running at around 4.3V or something like that, meaning that you are inputting 1182.5mW of power and getting out 75mW. So you are losing 1.1W to heat. Now, consider... an LOC for example. If you put in 420mA at 3V to it, you can probably expect it to output at least 250mW. However, your input is 1260mW of power, so you are only losing 1.01W in this case. However, note that, you always need a heatsink for an LOC, especially at those currents. The same should theoretically be true of a 445 - just because the current is low doesn't mean it needs less heatsinking. Because it's near threshold, it is actually extraordinarily inefficient at those currents.
 
I think I will do that, but I don't have an LPM. :/ What if I just used a custom, aixiz-style copper module head for the diode? Also, Moh, any suggestions on driver type and power supply?
And thanks Wolf! That makes sense, now keep in mind, this my first 445 build, so I'm not sure how much heatsinking is appropriate for a 445. Also, if I'm running the diode this low, will it's life decreased?
 
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No problem! Regarding heatsinking: just a normal -sized heatsink is appropriate for 445s. They can handle a lot more, so proportionately speaking, it's probably the same size heatsink as you would need for a normal red LPC, i.e. just standard, flashlight-fit heatsink. Certainly a copper module would help, it may even be enough, but I always like to be on the safe side of things.

And lifespan... no. At most, it will probably actually increase the lifespan dramatically, giving you more than 10,000 hours of use, probably.
 
Well great! Can't wait to build my first blue laser. :) Now, as far as thermal properties go, I don't really care about burning much, but it would be nice to be able to start some steel wool for a fire-starter. Would this be possible with 75mw of 445? Or would it need to be cranked up?
 
Lighting steel wool isn't easy :P You may be able to light a match with 75mW (that's iffy), but I'm not even sure if you could light steel wool with 1W of power =p
 
Oh wow, okay! I thought I had heard about some of the lower power 405's igniting steel wool, I haven't tested it myself. Well, do you know of anything that makes decent laser tinder? I've seen some rocket fuel-type charges that seemed cool, it would just be nice to have a waterproof and winderproof fire starter. But, I would rather stay on the lower power end. <150mw.
 
I'll give it a shot! Thanks for the help! I need to +rep both Wolf, and Moh, I will as soon as i'm able. :) As for the build, i'm going to run it off of a single 16340 most likely. What driver would you suggest? It will most likely need to fit into the aixiz housing..
 
Hey, no problem. Regarding driver... I would probably suggest a flexdrive - it's always a great option for a driver, and it's tiny. It's pretty expensive ($26 shipped), but it's really great.
 
That's what I thought you'd say, haha. I should be using an A140 for this right?
 
Try an M140 - they are the diodes that most people have nowadays and they seem to be more efficient.
 
you'll have to get a flex drive to power it since you're using a single 16340.

What are you putting it in? is it lab style or handheld?
 
It's going to be handheld. I haven't decided what host yet, I bought a few of those waterproof rayfoss hosts, I think It would be pretty nice in there. :)
 
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