A Peek into Ryan's Builds: Heatsinking a Hot Linear Driver

[steveclv]

More heatsinking on the driver would more heat from the driver to the diode...

Heat is drawn from hot to cold - so this would depend upon how much heat is being generated by the 'overdriven' diode - I suspect they get pretty freakin hot!!

 

[RyanElectro]

Sorry, what i meant was there is no need to get a solid piece of copper for the driver,
because the finned one is clearly working fine

Oh! I read it wrong And yes very true! Especially since I don't recommend running it longer than 90s at a time.

 

[justinjja]

Heat is drawn from hot to cold - so this would depend upon how much heat is being generated by the 'overdriven' diode - I suspect they get pretty freakin hot!!

Heat sink equations are always fun... Lol
The diode probably does put out more wattage than the driver,
But there are several thermal junctions from the diode the the driver heatsink.

 

[tsteele93]

Sorry, what i meant was there is no need to get a solid piece of copper for the driver, because the finned one is clearly working fine

Well done! A lot of people would have gotten upset and started firing back on the first misunderstanding (I knew what you meant the first time) but you just stepped back and re-stated your point without starting a fire.

Good form AND I agree with you - yes a larger hunk of solid copper would be nice, but these finned style heat-sinks are cheap and easy to get and I haven't found good "chunks" of copper in the right size yet. So these sinks make a good option, especially if people do as Ryan says and make sure they press tightly against the pill.

Also, I have sawed several of these in half, and like another poster mentioned, I was worried they might be "Chinese Copper" aka, copper plated lead or worse. But they appear to be good red copper all the way through.

One other note, both these and the longer finned versions I posted above, come with a thermal epoxy on the heat sink. If you could just use it, you could stick them right on the driver and be done, but unfortunately the grinding or cutting needed to make them fit often messes up the epoxy. So you are left sanding them, cleaning them and applying them to the pill.

I think a lot of people are getting caught up in the theoretical and not seeing the practical. In theory a solid piece of copper, just the right size would be best. But practically, these sinks are relatively inexpensive, easily available and able to do the job.

I DO like the idea of adding solder to the gaps to increase the mass/conductivity vs the air gaps, but I'm not sure it is needed.

One other thing, I know there are a lot of folks who seem ready to look very hard for any "chinks in the armor" because Ryan has come on board "full-steam ahead" and is selling lasers very fast. But I think he is trying to show that he is doing quality builds.

I've seen plenty of builds where the person didn't even bother to sink the pill - which is fine if you are running low currrent or are willing to deal with shorter duty cycles. But I think it is a good sign when someone is trying to "over-engineer" with as much heat sinking as possible.

And believe it or not, in my experience adding heat sinking/paths from the driver to the pill or body or diode heat sink is one of the most challenging parts of doing a tight build.

Once you add a square block of metal to the backside of the pill, you DRASTICALLY reduce your working area and you create a real hassle for wiring at that point too. Wires that would have travelled freely now want to twist. More care has to be taken in the order that you do things, it really adds a lot of work and challenge to the build.

To me, that shows that someone is trying to do things right. It is a lot harder to do, but worth doing. It also shows he is willing to be transparent and show how he is doing things. There are plenty of people out there who are "perfect" because they never let you see what is behind the curtain and/or never admit to mistakes. I have more respect for someone who is willing to show their cards and accept input from others and learn and improve their build quality from the forum's collective knowledge.

In the end, if people buy Ryan's lasers and have problems - it will be quickly exposed. If they buy them and they are quality builds, then that will be shared as well.

My only constructive criticism for you Ryan, is slow down a little when you respond and make sure you aren't being defensive. You handle things pretty well, but just be careful not to jump the gun or see an "attack" where there is none.

 

[JLSE]

One of the vets...either rhd , or wannabu...err SJLL...JLS..cant remember what he's changed his name too, the one with the muppet charactor burning his hair with a laser, has done a few builds with the driver directly heatsinked to the body of the laser, I'll see if I can find them.

lol...JLSE

I put my drivers tight to the body, but I also dont use drivers that generate much
heat.

With a high power build you are not only looking to conserve battery power
where you can, but also let the diode do all the heating in the host.

Any driver that gets hot enough for thermal reg. to kick in, is working against
you.

:beer:

 

[RyanElectro]

Well done! A lot of people would have gotten upset and started firing back on the first misunderstanding (I knew what you meant the first time) but you just stepped back and re-stated your point without starting a fire.

Good form AND I agree with you - yes a larger hunk of solid copper would be nice, but these finned style heat-sinks are cheap and easy to get and I haven't found good "chunks" of copper in the right size yet. So these sinks make a good option, especially if people do as Ryan says and make sure they press tightly against the pill.

Also, I have sawed several of these in half, and like another poster mentioned, I was worried they might be "Chinese Copper" aka, copper plated lead or worse. But they appear to be good red copper all the way through.

One other note, both these and the longer finned versions I posted above, come with a thermal epoxy on the heat sink. If you could just use it, you could stick them right on the driver and be done, but unfortunately the grinding or cutting needed to make them fit often messes up the epoxy. So you are left sanding them, cleaning them and applying them to the pill.

I think a lot of people are getting caught up in the theoretical and not seeing the practical. In theory a solid piece of copper, just the right size would be best. But practically, these sinks are relatively inexpensive, easily available and able to do the job.

I DO like the idea of adding solder to the gaps to increase the mass/conductivity vs the air gaps, but I'm not sure it is needed.

One other thing, I know there are a lot of folks who seem ready to look very hard for any "chinks in the armor" because Ryan has come on board "full-steam ahead" and is selling lasers very fast. But I think he is trying to show that he is doing quality builds.

I've seen plenty of builds where the person didn't even bother to sink the pill - which is fine if you are running low currrent or are willing to deal with shorter duty cycles. But I think it is a good sign when someone is trying to "over-engineer" with as much heat sinking as possible.

And believe it or not, in my experience adding heat sinking/paths from the driver to the pill or body or diode heat sink is one of the most challenging parts of doing a tight build.

Once you add a square block of metal to the backside of the pill, you DRASTICALLY reduce your working area and you create a real hassle for wiring at that point too. Wires that would have travelled freely now want to twist. More care has to be taken in the order that you do things, it really adds a lot of work and challenge to the build.

To me, that shows that someone is trying to do things right. It is a lot harder to do, but worth doing. It also shows he is willing to be transparent and show how he is doing things. There are plenty of people out there who are "perfect" because they never let you see what is behind the curtain and/or never admit to mistakes. I have more respect for someone who is willing to show their cards and accept input from others and learn and improve their build quality from the forum's collective knowledge.

In the end, if people buy Ryan's lasers and have problems - it will be quickly exposed. If they buy them and they are quality builds, then that will be shared as well.

My only constructive criticism for you Ryan, is slow down a little when you respond and make sure you aren't being defensive. You handle things pretty well, but just be careful not to jump the gun or see an "attack" where there is none.

Well, Tom I think that basically sums up all the noteworthy points. heh :beer: