PowermanKW
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Sweet, I can skip the MH and do a T5 fixture with LEDs for effect.
DIY LEDs - The write-up
- Thread starter JohnL
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Sweet, I can skip the MH and do a T5 fixture with LEDs for effect.
kcress
New member
Yep indeed.
Reef_Matrix29
Water Lover
Make sure you post pics of your build. Do you know which color LEDs you will accent with to get the shimmer you are looking for?
terahz
1x10^12 Hz
Yes, they are 12V fans 2x2 in series for the 24V supply.
Since I'm using arduino to control the LEDs, I'll probably use the same for the fans. Unfortunately they don't have control wires (just one that reports RPM) so I'll have to think that a bit. I don't mind them running at full speed during the day (they keep the LEDs at 47C vs 61C) but at night, when the blues are dimmed for moonlight, I might even turn off the fans, so I do want to be able to control them via Arduino. Too bad the weekend is over
.PowermanKW
New member
No idea. Probably won't happen for a bit. I'm set now, but want to move up at some point. Was just looking whether my light will work or if I will have to go with something else. I think my light will work, but now I want to go to T5s.
der_wille_zur_macht
Team RC
If you're going to be upgrading, why not go all LED?
terahz
1x10^12 Hz
yes. I didn't want to add a second supply just for 4 fans.
Hesham
Always learning!
Yes, they are 12V fans 2x2 in series for the 24V supply.
Since I'm using arduino to control the LEDs, I'll probably use the same for the fans. Unfortunately they don't have control wires (just one that reports RPM) so I'll have to think that a bit. I don't mind them running at full speed during the day (they keep the LEDs at 47C vs 61C) but at night, when the blues are dimmed for moonlight, I might even turn off the fans, so I do want to be able to control them via Arduino. Too bad the weekend is over
Hi Terahz - great job with the LED retrofit. I very much like your idea of using an array of low cost heat sinks.
Are the fans blowing in or sucking out? Generally, it is better (less turbulence, not fighting natural convection currents, reduced pressure increase within the enclosure, reduced noise, etc) for the fans to blow out. Air is drawn through available slots and then pulled out by the fans. You may also have fans blowing in on one side of the fixture and blowing out on the other side. Inlet and outlet holes need to be similarly sized regardless of approach. By blowing out and having similar sized outlet holes, noise from air moving through the fixture will also be reduced a little.
Fans should typically blow inwards only when the air is ducted directly to the object being cooled (such as a fan over a processor). This is still supplemented by a mechanism to take the heated air out of the unit.
You may be able to get away with eliminating some of the fans and/or run them at lower speed. Now that you have a fixture, you can experiment.
terahz
1x10^12 Hz
Thanks
They are blowing the hot air out. There are some holes on the top for intake (previous hot air out for the original lights) so I think that will create a nice airflow.
I also thought of 2 in on one side and 2 out on the other, but I think with the intake on the top this way is better.
Now my only challenge is to wire the 2 sets of fans with a couple of transistors (I still can't figure out, do I need PNP or NPN?) to the arduino for some fan control. That will be the hardest part yet.
As you said, I can go without the fans at all. Temperature-wise the leds stay at a bit over 60C after a few hours of operation, which is quite good.
PowermanKW
New member
I might at the time, but they are still sort of new. New things come at a premium. Then it takes a while for everyone to jump on the band wagon and start to offer a lot of diversity. We will see what is around when the time comes.
PowermanKW
New member
One thing to consider though is fans blowing in move more air. Cold air is pumped into the fixture to cool the components. Fans exhausting hot air do not move as much. Plus, the components have already been heated and now we are just exhausting hot, less dense air
kcress
New member
I disagree. Fans blowing out are vastly superior to fans blowing in. Just look at PCs, you will NEVER see one with fans blowing in. Every one wants to reduce costs. Having to use twice as many fans to get the same cooling is not a cost reducing setup.
terahz; I was thinking of something like these. They don't need any particular fans. They work with all the typical pancake fans.
http://www.svc.com/zm-fanmate2-75.html
terahz; I was thinking of something like these. They don't need any particular fans. They work with all the typical pancake fans.
http://www.svc.com/zm-fanmate2-75.html
terahz
1x10^12 Hz
I'll stick with blowing out. I also thing it is better to take the hot air out. Might run some tests if I'm not too lazy but so far it works fine.
kcress, these controllers look nice, however the fanmate2 will not with 12V fans. Also I don't want manual control. I'm just thinking of a simple arduino -> transistor -> 24V line hookup (with some resistors in between). I'm still trying to figure out the parameters of the transistor though. I think VEBO should be 5V (that's the max of the arduino), VCEO should be at lest 24V but that's about as much as I can figure out. the fans are 70mA each, so 140mA for each circuit of 2 fans, however I'm not clear on the PNP/NPN part and the operating frequency part and there is power dissipation.... I should have taken some EE classes in college.
Sorry if this is going a bit off topic, but I'm sure other people might want active, programmable cooling for their LEDs.
kcress, these controllers look nice, however the fanmate2 will not with 12V fans. Also I don't want manual control. I'm just thinking of a simple arduino -> transistor -> 24V line hookup (with some resistors in between). I'm still trying to figure out the parameters of the transistor though. I think VEBO should be 5V (that's the max of the arduino), VCEO should be at lest 24V but that's about as much as I can figure out. the fans are 70mA each, so 140mA for each circuit of 2 fans, however I'm not clear on the PNP/NPN part and the operating frequency part and there is power dissipation.... I should have taken some EE classes in college.
Sorry if this is going a bit off topic, but I'm sure other people might want active, programmable cooling for their LEDs.
PowermanKW
New member
You want to qualify that.... vastly superior in what way??? Heat transfer is not that complicated. I'm not saying blowing in is the "vastly superior" method. It just depends on the application.
A PC's major heat generator is the CPU. Air is drawn in the cabinet to keep it cool and pulls air across the CPU and exhausts it. If you blew air in on the cpu you would be able to cool the CPU much better with a smaller fan, but you would put all that heat into the cabinet. Exhausting hot air requires a larger fan to move the same amount of air compared to cold. It has nothing to do with cost savings, it has to do with it working.
Things are designed with certain criteria. You with your off the shelf fan can cool an enclosure and the components inside better blowing cold air in. Look at many other lighting fixtures that blow air in. It's been done plenty.
stugray
Premium Member
PowermanKW,
I have built a variable speed fan controller before using the PWM function on a microcontroller.
I believe the arduino has PWM built in. Is it 5 VDC output logic levels?
If so, you can directly control a N-type FET an "dim" the fans.
BTW - what part of Colorado are you in?
Stu
I have built a variable speed fan controller before using the PWM function on a microcontroller.
I believe the arduino has PWM built in. Is it 5 VDC output logic levels?
If so, you can directly control a N-type FET an "dim" the fans.
BTW - what part of Colorado are you in?
Stu
PowermanKW
New member
Springs. I'm up your way every now and then.
yupgopotty
New member
Not sure who you're referring to, but I got my LEDs from rapid led. I did get the meanwell drivers as part of a larger kit. By turnaround do you mean shipping time? It was pretty quick, I don't remember exactly but I'd say I received the goods in about 2 days. No fancy packaging or anything but everything I ordered was in the box and it came pretty quickly.
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