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Survival Laser S4X duty cycle

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Hello,

I have been planning to build a laser for quite some months now, but I ended up spending almost all my money an a mechanical keyboark because my old one broke.
For now, I'm planning to do an S4X build probably around November, as my allowance is only 50 cents a day so it takes a LOOOONG time to get all the money I'll need for the build.

So, my question is: what's the duty cycle if I use a PLTB450B diode @1.25A on the S4X host with an extender and tapered copper heatsink, an extended copper heatsink, a copper heatsink, and an aluminum heatsink, with thermal paste between the heatsink and the host? I want to compare the duty cycles of those heatsinks so that I don't waste money on an overkill heatsink (I'm looking for a >2mins on duty cycle).

Thanks
 
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GSS

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I'm under the assumption the SX4 host can only take one sink whether it a extended copper or AL, and the host head is thicker. I can see the 2 minutes you want with it set at 1.25A with a copper sink.
 
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Thanks for the reply, I know that you can only use one, I asked for the duty cycle of each heatsink, not with all of them inside the host.
 
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copper heatsink is good but i think aluminium is better in this case
A copperheatsink is only good when they are covered by an outer layer of aluminum, as they keep the heat for quite some time
and a copperheatsink will make you feel uncomfortable because they are hot when run long - while aluminum is cooler and if you put driver at 1.25 A you can use 2 min no problems
-i think so
 
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Encap

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Nobody is going to be able to tell you the specific run time of each of the four heats sinks used with an SX4 and your diode/driver setting choice unless they have tested each one especially when you say >2 minutes---how much greater?

Contact Gary at Survival Laser and ask him--maybe he had data to go by. See: https://www.survivallaser.com/storepage556085.aspx
 
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GSS

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Nobody is going to be able to tell you the specific run time of each of the four heats sinks used with an SX4 and you diode/driver setting choice unless they have tested each one especially when you say >2 minutes---how much greater?

Contact Gary at Survival Laser and ask him--maybe he had data to go by. See: https://www.survivallaser.com/storepage556085.aspx
This ^^^^^^^
If it gives you a little assurance Survival Lasers claims 2 minutes on and 1 off for his 7W SX4 build..
 

BowtieGuy

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I agree with these guys ^^^^, also, there won't be any "overkill" using any of those mentioned heatsinks, as Encap mentioned, contact Gary at Survival Laser.
 

Benm

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I'd advise against buying -any- laser pointer that has a limited duty cycle.

This is just bad thermal design, and while it may work fine, having something like 2 minutes on and 1 minute off is silly. That just means the heatsinking on the host is 2/3rd's of what it should actually be, i.e. they should have made that host a bit bigger or ran it at lower power so it could be operated continuously without worry.

Also: look at what ambient temperature that duty cycle is, there is a big difference between operating it at say 15 vs 35 degrees ambient temperature, with the latter not being that crazy high depending on where you live.
 

Lifetime17

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H,
Basically if you need to run that long you will need a heat sink with a lot of mass as in a mag light build. These sinks are very large and for the PLTB450B diode this would give you a longer cycle , But 2 min I wouldn't punish any diode that long.

Rich:)
 

paul1598419

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copper heatsink is good but i think aluminium is better in this case
A copperheatsink is only good when they are covered by an outer layer of aluminum, as they keep the heat for quite some time
and a copperheatsink will make you feel uncomfortable because they are hot when run long - while aluminum is cooler and if you put driver at 1.25 A you can use 2 min no problems
-i think so
Copper has a 1.6 greater thermal conductivity than aluminum. Some people think that aluminum magically releases its heat into the air better than copper, but there is no scientific evidence to corroborate this. Thermal conductivity is a finite property of a material to store and release energy as heat. The release into the surrounding air depends mainly on surface area and ambient temperature.
 

Richie89

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i would think 2 minutes would be perfectly fine with that setup because my PLTB450B is running at 1.8amps with an AL sink for module with no heatsink for my driver, i used compound between module and heatsink but im getting over 2 watts with my G2 and i run it all the time at 60 seconds no problem and it gets pretty warm but i always allow it at least 3 min for cool down, everything seems fine.
 

dden4012

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Consider the space requirements. Using the driver shelf pill and a half sized copper back half will give a good fit. The diode/driver module with the aluminum back half may have to protrude from the hosts heatsink due to available space.
Send SL an email or pm Garoq with your concerns as he can give you first hand specifics about the clearances.
 
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Thamks for the replies. I guess I'll just go with the extended and tapered copper heatsink, because it is not that much more expensive than the regular and extended copper ones. I am considering using the SS host instead as it looks really good.
 

GSS

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Thamks for the replies. I guess I'll just go with the extended and tapered copper heatsink, because it is not that much more expensive than the regular and extended copper ones. I am considering using the SS host instead as it looks really good.
SS is not a good heat conductor..
 

BowtieGuy

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^^^^ Exactly ^^^^, while you can argue aluminum vs. copper for the best heatsink material, a stainless steel host will not be as good as the aluminum S4X host, especially since the S4X is 1.5 times bigger than SL's stainless hosts.

None of this really matters as long as you're happy with what you purchase and are aware of its limitations; there are many hosts made of SS out there.
I myself am a sucker for a nice SS or even better, a titanium host, knowing that neither is very good at heatsinking. ;)
 
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Richie89

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^^^^ Exactly ^^^^, while you can argue aluminum vs. copper for the best heatsink material, a stainless steel host will not be as good as the aluminum S4X host, especially since the S4X is 1.5 times bigger than SL's stainless hosts.

None of this really matters as long as you're happy with what you purchase and are aware of its limitations; there are many hosts made of SS out there.
I myself am a sucker for a nice SS or even better, a titanium host, knowing that neither is very good at heatsinking. ;)
That is so crazy how a friend of mine told me a long time ago that SS wasn’t very good for thermal conductivity and I didn’t believe him, I know now that he was right lol
 




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