2x NICHIAs NDG7475 520nm 1W COOLING TEST

[norty303]

My last P73's built were over 800mW each at spec sheet current. I really wouldn't worry about thermal damage.
If you're using cube and cylinders for correction I'd say you're fine to a pair up for 1500mW after optics.

[planters]

jors,
I read post #25 and the problem is that he states that they will overheat if passively cooled, but if tightly coupled to the base plate (thermally) with grease or indium foil then even with just the brass cubes this requires that the base plate overheats. These low heat loads of a few watts (1A x 2.7V) are not going to produce much of a gradient even in brass and almost none in your copper mounts. His example is kinda anecdotal. What is the ambient temperature? What is the temperature that the base plate reached?...You should be fine.

But, here is what I suggest. Be a scientist. Don't accept these statements by norty, buffo or me as anything other than guides as to how to set up an experiment. You are interested in thermal issues (as am I) order a thermistor based temperature meter. I love the Apollo's. The probes on these are very small at around 1mm in diameter. Drill holes in the sides of Dave's mounts into the bulk of the copper (careful, copper is nasty) and into the base plate near where you plan to mount the diodes. These holes are so small they remain inconspicuous. Record the temperature changes as you change the operating parameters, fans and ambient temperature and demonstrate the results. We all get to benefit from this. You could even make a video. Once you really know what is going on then you will be more confident in designing the projector. Who knows? Maybe you can crank these a lot harder than you thought.

[dave]

I was actually thinking after you emailed me - What TECS are you using? Are they brand name ones? If not, I would try good quality ones from somewhere like digikey..

[jors]

Thanks guys, I can't live without you
Months ago tried chinese ebay tecs, but they are so inneficient (or perhaps had bad luck), poor cooling and lots of heat, so now:
on first setup I cooled greens and blues with 4x wimo 12703 (35w each)
on 2nd setup, greens and blues passively, and 2x mitsus teced with one digikey peltier 430874-301 (24v 6A). Yes, I know this is too much for 2 mitsus only, but my tec controller takes care and only delivers the necessary current to reach the target temp.

And yes Eric, I need some more red for a good rgb balance, so my next step is a P73 quad (Dave! new f2s order soon! )
First, I'll try 800mw for a 3,2w passively, then, want to cool mitsus with two wimo 35w in series (at 24v) at...say 20C and push them at 3,8w. Depending on baseplate temp I will go with tec or passively for reds.
thanks!