DIY LEDs - The write-up
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der_wille_zur_macht
Team RC
Where'd you get them from?
Can anybody tell me how to measure current on the meanwell with a multimeter? maybe i'm just stupid, but i turned the knob to the A with the squiggly line over it. The instructions said to set it to the max setting so you don't blow the meter so i put it to the 10A setting, black lead in the COM terminal and red lead into the 10A terminal. I then connect it to the red/black leads from the meanwell and i am getting a reading of 0.29 when the current pot is turned all the way down and 0.36 when it is turned all the way up. Am I measuring it correctly?
der_wille_zur_macht
Team RC
How exactly are you making this connection? Is there a load on the driver (i.e. LEDs being driven)?
Current readings must be taken in series, as opposed to voltage readings, which are taken in parallel ("across" something).
When i measured voltage i measured straight across the meanwell, so you're saying to measure current i need to connect it in series with the LED string? As in connect pos lead from driver to beginning of string, negative out of the string to pos of MM and neg. of MM to neg. of driver? or am i totally off?
der_wille_zur_macht
Team RC
You're correct. You basically "break" the circuit and insert the multimeter as if it were another LED. Do this with the driver off, of course.
Hello!
So, after reading thousands of posts in this huge thread over the last weeks i finally reached "today". THANK YOU to everybody who contributed to this concentrate of led-knowhow. I did not often see a thread in an internet forum with that much information and so little anti-social behaviour! As of today pretty much all of my questions were answered along the thread and my current plan is heavily shaped by the questions and answers you posted here.
My project is a modular lamp for my 180g freshwater aquarium. I hope the fact that i don't have a reef (yet?) doesn't bother you in this thread. My questions are about the technical implementation and not about freshwater related stuff.
I'm pretty clear about the make/model of leds and their quantity. Its gonna be 3-4 modules of 16*6inches (40*15cm). Each module has 2 rows of 6 emitters (12 leds/module): 6 CREE XP-G R5 and 6 SSC S42182. I know salty speaking this is very low-end (my current lightning: 2*54W T5 fluorescent). Coral growth is cleary not my intention, but a low light planted open paludarium in the middle of my living room. My goals are no (!) spill of light, i dont want to be blinded when chilling out on my sofa
The modules themselves should have a very light and clean look and will be hanging from the ceiling. Hanging height of the lamps will be determined by experimentation (ordered examples of various optics to try different setups). It will be modular to have "light landscapes" in my tank, there will be hotspots and "completely dark" areas.
Some posts ago der_wille_zur_macht and others have mentioned they use/plan to use aluminium channels (U, square or solid) for their fixtures. Massive heatsinks as often used here isn't an option for me for aesthetical reasons, i'm really interested in more information about this kind of cooling technique. I remember a project in this thread that used 2 nested AL square tubes (leds mounted on the inner tube, sticking out through holes in the outer tube. As far as I remember the project was discontinued due to thermological concerns? Can't find it now unfortunately nor remember who wrote it...). I guess active cooling is a must in a channel setup?
I'm thinking about using 2 square tubes (width: 2 inches) of aluminium per module and mounting (srew or glue, tbd) the stars to the outer side of the tubes. The 2 tubes of the module are gonna be adjustable individually on at least one axis (idea stolen from widmer). Do you think one fan on one side driven at "unhearableV" would be enough? I'm aware this is hard to say, but maybe a rough guess of yours would be enough to shape my further thinkings.
der_wille, you mentioned the u-channels with active cooling. will there be enough airflow to cool the whole length of your channel?
extra thanks!
So, after reading thousands of posts in this huge thread over the last weeks i finally reached "today". THANK YOU to everybody who contributed to this concentrate of led-knowhow. I did not often see a thread in an internet forum with that much information and so little anti-social behaviour! As of today pretty much all of my questions were answered along the thread and my current plan is heavily shaped by the questions and answers you posted here.
My project is a modular lamp for my 180g freshwater aquarium. I hope the fact that i don't have a reef (yet?) doesn't bother you in this thread. My questions are about the technical implementation and not about freshwater related stuff.
I'm pretty clear about the make/model of leds and their quantity. Its gonna be 3-4 modules of 16*6inches (40*15cm). Each module has 2 rows of 6 emitters (12 leds/module): 6 CREE XP-G R5 and 6 SSC S42182. I know salty speaking this is very low-end (my current lightning: 2*54W T5 fluorescent). Coral growth is cleary not my intention, but a low light planted open paludarium in the middle of my living room. My goals are no (!) spill of light, i dont want to be blinded when chilling out on my sofa
The modules themselves should have a very light and clean look and will be hanging from the ceiling. Hanging height of the lamps will be determined by experimentation (ordered examples of various optics to try different setups). It will be modular to have "light landscapes" in my tank, there will be hotspots and "completely dark" areas.Some posts ago der_wille_zur_macht and others have mentioned they use/plan to use aluminium channels (U, square or solid) for their fixtures. Massive heatsinks as often used here isn't an option for me for aesthetical reasons, i'm really interested in more information about this kind of cooling technique. I remember a project in this thread that used 2 nested AL square tubes (leds mounted on the inner tube, sticking out through holes in the outer tube. As far as I remember the project was discontinued due to thermological concerns? Can't find it now unfortunately nor remember who wrote it...). I guess active cooling is a must in a channel setup?
I'm thinking about using 2 square tubes (width: 2 inches) of aluminium per module and mounting (srew or glue, tbd) the stars to the outer side of the tubes. The 2 tubes of the module are gonna be adjustable individually on at least one axis (idea stolen from widmer
). Do you think one fan on one side driven at "unhearableV" would be enough? I'm aware this is hard to say, but maybe a rough guess of yours would be enough to shape my further thinkings.der_wille, you mentioned the u-channels with active cooling. will there be enough airflow to cool the whole length of your channel?
extra thanks!
Neogenocide
New member
Welcome
I'll throw this out. I built a setup for a freshwater tank using 3/4" U channel. 6 ft length, 6 led's per strip. I am not having to use any fans, they barely get warm to the touch. It's the best thing I ever did for my FW 125G tank.
Scott
I'll throw this out. I built a setup for a freshwater tank using 3/4" U channel. 6 ft length, 6 led's per strip. I am not having to use any fans, they barely get warm to the touch. It's the best thing I ever did for my FW 125G tank.
Scott
der_wille_zur_macht
Team RC
Scott, what color LEDs did you use? Is the tank planted?
Within the next week or two I'm swapping my son's 10g planted FW tank to a new stand, and I'll probably throw LEDs on it at that point instead of the PCs on it now.
Within the next week or two I'm swapping my son's 10g planted FW tank to a new stand, and I'll probably throw LEDs on it at that point instead of the PCs on it now.
ok so i finally wired everything up correctly. However i am only seeing a max of 0.74 amps even though i have both pots turned to full. is this right? I have a 13 LED string.
der_wille_zur_macht
Team RC
What LEDs are they? I'm guessing with 13 LEDs you may be beyond the max the driver can hit. What voltage are you seeing?
Neogenocide
New member
Unfortunately with African Cichlids, plants don't last long. I can tell you 12 LED's on a 125G tank is not incredibly bright, but what algae is setting in is getting eaten by the fish. I would say a few more LED's would easily make it capable of plant growth.
As far as LED's using Q4 Cree LED's. Mind you they are also somewhat dimmed as I haven't taken the time to order a 10v power supply for the dimming circuit. I just used what I found in my junk box which I think was 7.4v.
Scott
kcress
New member
extra; Welcome to RC. Normally square tube is no way near as good as U or angle iron for heat sinking. The reason is because a large part of heat sink function is radiation. This is where the temperature of the sink is higher than the surrounding materials. When this happens heat leaves the sink as light on it's way to these cooler surfaces.
If you have an L section none of the surfaces see each other and so everything in sight is cooler and radiation cooling occurs.
With something like square tubing think about what any of the inner surfaces see... More of the same heatsink. This essentially prevents all radiation from the inside surfaces. Only the outside surfaces can participate and only if they aren't 'seeing' adjacent surfaces that are about the same temperature. To have any external radiation cooling happening on the top side the heat has to conduct across the face up the sides and around the corners to the back.
What this all means is if you need that shape for aesthetics or some other reason then go ahead. Make sure you force air somewhere. If the full tube isn't needed for structure or some other reason then use sheet, or angle, or U channel, and NOT tubing.
If you have an L section none of the surfaces see each other and so everything in sight is cooler and radiation cooling occurs.
With something like square tubing think about what any of the inner surfaces see... More of the same heatsink. This essentially prevents all radiation from the inside surfaces. Only the outside surfaces can participate and only if they aren't 'seeing' adjacent surfaces that are about the same temperature. To have any external radiation cooling happening on the top side the heat has to conduct across the face up the sides and around the corners to the back.
What this all means is if you need that shape for aesthetics or some other reason then go ahead. Make sure you force air somewhere. If the full tube isn't needed for structure or some other reason then use sheet, or angle, or U channel, and NOT tubing.
customcolor
New member
what if you put a laptop fan on the end of each square tube to force air through the entire square tubing??
now i have a question for ya....would cat5 wire or telephone wire be able to connect a meanwell to a led array with no lose of power? or is it to thin of a wire..... just thinking of a quick disconnect....
now i have a question for ya....would cat5 wire or telephone wire be able to connect a meanwell to a led array with no lose of power? or is it to thin of a wire..... just thinking of a quick disconnect....
tahiriqbal
Sialkot
It seems you are using Meanwell ELN-60-48 (P or D) version of the LED driver. If that is the case then you need to open up the driver with great care, you will see a screw which you could turn to adjust the voltage. With this option your driver could be fully turned up to just over 1.2Amp and lowest is just under 987mA (I think). These drivers could handle load up to 52volt or just over but it is not advisable, what I would say reduce the number of LEDs to 12 per string and turn your Meanwell's internal POT to full and Walla........Y
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