ThermoElectric Coolers (TECs)

falchionsmight said:

Daedal, I'm glad I could find something that hadn't be known already, lol. It's a pleasure to find something useful for you, you've done so much for me, it's nice to give back a bit. I wonder if they'd send you a "sample one" for testing, you've got so many DIY lasers, you'd be perfect for giving them a review of it...

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Thank you very much falchionsmight, I appreciate your kind words. I have done just that. I asked to be sent one for testing and for the possibility of much larger orders later on. I am still wondering how I'd incorporate it though. I don't even know what the "holes" look like! :-/ It's some kind of a press-fit for the diodes, then the collimating would have to be done elsewhere. I'm sure I can rig up a nice aluminum housing for it nonetheless. The lens would have to be installed in a plastic shell to protect it from excessive heating/cooling for condensation and safety. The hot side would have to be sinked to the flashlight... Hmm... this may work out if the TEC itself is not very huge and could possibly fit in a flashlight like the one I used in my latest mod...

http://www.laserpointerforums.com/forums/YaBB.pl?num=1186966870

Regardless... that was an astonishing find! I'm still very excited about this TEC if I get one for review. I'll let you all know what comes up

Thanx;
DDL

I will personally say that Pseudo's TECs are amazingly useful and very nice. They are well made and very powerful. Needless to say as well, they are excellently packaged. These things could easily boil a cup of water in no time! Or freeze it if you'd like too... ;D

--DDL

Psuedo, it sounds like you might have what I'm looking for. To be honest, I don't know anything about TECS, beyond the basic ideas of apply voltage, make sure there's a heat sink on the hot side, and make a thermal connection to the cold side and what needs cooling. Beyond that, I know nothing of the voltage I need it to run at, or what wattage I need (or how many watts I need to move of the diode). I'm planning on using this for my 18x DVD burner diode, and for my 3 group buy diodes, if that helps any.

Using TECs in low voltage "hardy" electronics is as simple as you say.
Add power, sink the hot side, use the cold side.
When they are used on CPUs you have to be very careful of condenstation and even icicles!
CPU TECs are generally run full power so can promote ice formation in seconds. Within minutes you have a frosted icecube, if that ice touches the CPU die, pins or the motherboard, game over.

PM sent.

pseudonomen137 said:

I used to sell lots of 10 TECs on eBay. What are you looking for? I have a bunch of TECs still in stock that I may be able to sell you.

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The tiny peltiers Hamlock Mike and I got off of e-bay are only around 4 watts. If I run it at 3 volts, it draws only 500ma of current so it would be consuming 1.5 watts. Even with this low of a power, it will freeze the module with the diode turned on. Unfortunately he no longer has them listed or I would post the link to them.

Condensation is another problem to deal with. The module develops condensation even when powered by 3 volts. I am going to try to lower the voltage more so I can just have it be cool and not freezing with the diode running.

Here is a small update to my previous post. I ran the peltier with only 200ma's of current. It was hooked up to one nimh battery. It kept the module cool, while I was driving the diode with 190ma's of current. There was NO condensation. And on man, does it burn.. ;D I wish I would have known this before I glued it to a big heat sink. But it will keep the peltier cool with no fan needed.

We're back to the old Voltage or current thing here .....

You want to feed the TEC (Peltier) what current is needed to COOL the LD. You don't want to freeze it. We are trying to maintain ~20 C on the heatsink to prolong LD life at high current. Also, Don't get it so cold that water starts getting on everything.

Mike

Funny ---- THe LD at 190 mA current and the TEC at 200 mA  --  Both probably at around 3.5 volts !!!  Do I see some sort of balance here ??

Stop thinking VOLTS.  Everyone asks "how much current?"  In this solid state science, current is KING.......  We have been brought up in a world of 120 VAC, 12 VDC, 5 VDC 240 VAC ---etc.   It's different in this area of electronics.

Mike  

Yeah, I lost my first diode last night from the GB...I think I let it get too wet.. ;D
Another thing that definitely does help with the smaller Aixiz modules is to put some arctic silver compound (not the glue) on the threads. The way I did mine was to glue only the part that holds the lens to the peltier. That arctic silver adhesive is good stuff.

Yup, we need to think in terms of current, I finally got that through my thick skull. I did not even bother to measure the voltage going to the diode. But when the peltier was drawing 200ma's, I had only ONE nimh battery hooked up to it...so about 1.2 volts. This keeps everything cool, at least when driving the diode with 190ma's.

Gazoo --

I use A5 grease for everything laser .. I do need the A5 adhesive to "glue" my Aixiz module holder to the cold plate ( it didn't come today either  )   ....

A5 glue is for non-adjustable things opposed to focusing threads.  

Damn, I want to push one of these GB diodes to 400 mW !!!!!

Mike

Added:  You need to know the voltage required to get the desired current.  
Voltage is only secondary to me in this relm.  That's why DDL posted his basic current source for everyone.

Here is a picture to give you an idea of how I mounted the peltier, and for those that don't know, how small it actually is. That is the smaller Aixiz module glued to the peltier. I know my PDA camera sucks...sorry. The fan is at the bottom of the heat sink and will probably never be used.

Gazoo, that is AWESOME! Quite the heat sink for the laser. I'm impressed. I'm going to be ordering my TECs in a few days, maybe I'll grab a cheap CPU heat sink while I'm at it. Thanks for showing us your setup. So how well does the laser work with that heat sink attached to it? Is that the LM317 jutting out from the PCB? What are you using to drive the TEC? Looks good, keep us posted on how well it works.

Yes, that is the LM317, and in the upper left hand corner are two 2.2 ohm 5 watt resistors...lol. This is what is driving the diode with a 4.5 volt supply. I will be replacing the 5 watt resistors with a 3 watt rheostat. I ordered 3 from Rat Shack. I will also probably need to bump the voltage up to 6 volts.

As far as the peltier....I am currently powering it with only one AA nimh battery. But when the rheostats get here, I will be mounting an LM317 on the other side and controlling the current going into it just like we do the diode.

For power, I have a Rat Shack 3 amp 12 volt power supply, with a cigarette lighter jack built into it. I have one of those power adapters plugged into the lighter jack. It is a switching supply and can be set to 3, 4.5, 6, 7.5, 9 and 12 volts.

I plan to power the TEC and diode with this same power supply and this is why I will probably need to bump up the voltage to 6 volts.

I am kicking myself in the rear because I should have ordered two of those peltiers. They are so small and draw so little current it would be easy to cool down anything with them, including a flashlight modded into a laser. The peltier is only drawing 200 ma of current, connected to one AA nimh battery, and this is plenty to keep the diode cooled at well below room temperature.

Well, well well, he relisted them. He has some other nice peltiers too, but I like these. Going to order another one.

http://cgi.ebay.com/Peltier-Junctio...49587368QQihZ006QQcategoryZ4661QQcmdZViewItem