Yeah kinda like a cool tube. Go for it.
One thing I can foresee is it being very hard to assemble/wire without large openings on top. Perhaps preassembling and then sliding the preassembly into the vinyl post would make it easier.
Pictures of your DIY lights - Post your pics!!!
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One thing I can foresee is it being very hard to assemble/wire without large openings on top. Perhaps preassembling and then sliding the preassembly into the vinyl post would make it easier.
Meinolf
Well-Known Member
I also like the idea to capsule the fixture very much, because it gives a more finished look, eases the handling and helps against moisture. The fence posts are nice and cheap, too. For greenhouse lighting, the reflective surface doesn't consume too much sunlight.
But whenever you put a case around the heatsinks, it requires more effort to get rid of the heat evenly. In case of the obvious cool tube design, you would need more powerful fans to create the needed backpressure. Even then, there would be a temperature gradient between the first and the last heatsink. I am sure this would be failsafe (on moderate currents) but might add significant temp droop penalty. Also, if you don't guide the air directly through the fins, a lot of air will follow the lowest resistance, probably flowing around the heatsink.
Sure, cutting large holes in the tube will help a lot, but denies the system prerequisites of a very clean look and moisture protection, in my opinion. This is criticism on a high level, of course. After all, your light pole is still outstanding.
But whenever you put a case around the heatsinks, it requires more effort to get rid of the heat evenly. In case of the obvious cool tube design, you would need more powerful fans to create the needed backpressure. Even then, there would be a temperature gradient between the first and the last heatsink. I am sure this would be failsafe (on moderate currents) but might add significant temp droop penalty. Also, if you don't guide the air directly through the fins, a lot of air will follow the lowest resistance, probably flowing around the heatsink.
Sure, cutting large holes in the tube will help a lot, but denies the system prerequisites of a very clean look and moisture protection, in my opinion. This is criticism on a high level, of course. After all, your light pole is still outstanding.
Growmau5
Well-Known Member
@Meinolf You make some excellent points, especially "air flows in the path of least resistance" The small finned cpu cooler is probably not best suited for an LED "cool tube" unless the sheer volume of air moving through the channel is enough to where the air has no choice but to pass through the fins. i guess someone will have to try it one day.
caretak3r
Well-Known Member
I did this very thing (with vinyl fence post and 2 fans):
http://rollitup.org/t/pictures-of-your-diy-lights-post-your-pics.871625/#post-11628822
bicit
Well-Known Member
I've been thinking about building a 'hood' for some heatsink usa profiles. The English language is failing me this morning, bare with me. On the most basic level I was thinking of getting some thin aluminum sheet for this task. Bending it over the heatsink to create a 'mound' over the top of the fins and riveting the sheet to the outer fins of the heatsink. Then make the end plates by getting more aluminum, cutting the appropriate sized hole and using a dryer vent take-off flange. Then attach it too the hood using a combination of brackets and rivets with silicon and duct tap to seal any leaks.
It wouldn't matter if the airflow passes directly through the fins. Better, but not mandatory IMO.
It wouldn't matter if the airflow passes directly through the fins. Better, but not mandatory IMO.
Meinolf
Well-Known Member
@caretak3r Yeah, nice. How long is the post? At what voltage do you run the Alpine fans? Have you got a thermo gun and can check on the temperature gradient between heatsink 1 and 3? By the way, as you use the light at an 45° angle, canopy intensity might benefit from some 90° reflectors. You could spraypaint such things white, they're flexible and you could shape the projection to some extent.
caretak3r
Well-Known Member
22", 7 degrees Fahrenheit difference between in and out side. The fans run @ 12V. I'll check temp difference on HS but it may not register well on the shiny surface.
bicit
Well-Known Member
Use a sharpie to mark the spot you want to measure. Should be able to get a reading that way.
Abiqua
Well-Known Member
I really like these Manual Reset Temperature Switches.....
Once it gets too hot, stays off until you reset or check the circuit.....that's why I won't ever use those Temp switches you have....liked them initially, but they can come back ON and that is a no no in circuit building imho....they won't stop a fire....
Tim Fox
Well-Known Member
Winner ,, YUPPP
I think apaches do that (small side mounted fans), GG should know
two minor cons though, you lose downward flow into the HS which cools better. unless you use a very deep case you lose the advantage of large fans (quieter and more efficient).
EfficientWatt
Well-Known Member
Nice,
do you have a link to share please ?
thanks
do you have a link to share please ?
thanks
I really like these Manual Reset Temperature Switches.....
Once it gets too hot, stays off until you reset or check the circuit.....that's why I won't ever use those Temp switches you have....liked them initially, but they can come back ON and that is a no no in circuit building imho....they won't stop a fire....
Abiqua
Well-Known Member
75 Celsius cut-off.....might be too high......probably is but might be really good for mid to high cob vF @ [75-150+ watts]
http://www.ebay.com/itm/250V-10A-NC-75C-Manual-Reset-Temperature-Switch-Thermostat-KSD301-2-Pcs-/321243616254?pt=LH_DefaultDomain_0&hash=item4acb9c93fe
Al Yamoni
Well-Known Member
It's as if Doc Oc were a grow light..
bicit
Well-Known Member
Something like this would work? Shut off temp is 160*f (71*C)or the second one at 135*F(57*C)I really like these Manual Reset Temperature Switches.....
Once it gets too hot, stays off until you reset or check the circuit.....that's why I won't ever use those Temp switches you have....liked them initially, but they can come back ON and that is a no no in circuit building imho....they won't stop a fire....
http://www.grainger.com/product/GRAINGER-APPROVED-Limit-Rollout-6UEC2?s_pp=false&picUrl=//static.grainger.com/rp/s/is/image/Grainger/6UEC2_AS01?$smthumb$
http://www.grainger.com/product/GRAINGER-APPROVED-Set-Limit-6UEC1?s_pp=false&picUrl=//static.grainger.com/rp/s/is/image/Grainger/6UEC1_AS01?$smthumb$
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You can get these for plenty cheaper on eBay. Same made in China pieces. These were too big for my build.
I took them out because I bought them at too low a cutoff temp. After thinking about it more, I don't think they are necessary. Already have a sink and fan. In fifteen years of building my own computers, I have yet to have a cpu fan fail. Lucky me. If one does fail I won't have a fire, I might have a burnt out cob, but I trust the fan will do its thing for years.
75 degrees centigrade seems like a good cutoff temp. although not ideal most decent quality leds will continue to run ok at 85 C, won't they ?
dandyrandy
Well-Known Member
I use these on my alpine 11. Microtemp 4136a. 58°c. I spread outer fin and insert in fin under fan. As long as the fan runs no problem. Even running 2.1a on a Vero 29. Pull the fan and within a minute it's open.