DIY LEDs - The write-up
- Thread starter JohnL
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I have seen some conflicting information regarding running meanwell 60-48d's in parallel.
My leds have a forward voltage of "3.2-3.7". I want to run two strings in parallel at 650ma, how many can I run? I have seen posts where people claim 14 per string is possible, and I have also seen posts saying you are limited to 12 per string, and yet others run 13... I just want to run the maximum safe amount of LED's per driver.
Just for my knowledge. If I wanted to run 3 strings in parallel I would be driving the leds at 433ma?
My leds have a forward voltage of "3.2-3.7". I want to run two strings in parallel at 650ma, how many can I run? I have seen posts where people claim 14 per string is possible, and I have also seen posts saying you are limited to 12 per string, and yet others run 13... I just want to run the maximum safe amount of LED's per driver.
Just for my knowledge. If I wanted to run 3 strings in parallel I would be driving the leds at 433ma?
brassmonkyballs
BMB
What type of LEDs? As you can imagine 3.2v-3.7 is a large range. For worst case divide the high end (3.7) into the driver voltage (48) that tells you how many you can run in series.
Your are correct about parallel strings.
I have personally made an actinic supplement fixture for a friend and its running 28 Cree XPE RBs in 2 strings of 14 off a meanwell ELN 60-48. its been running for about 4 months now with no problems.
They are bridgelux 3w leds, I plan to try Cree's later for other projects if everything goes OK with this build. 13 would be 48.1v. So, should I just wire up 12 and if I still have 3.7v left I can add one more, if I have 7.4v left I can add two more? I assume I can test these in a series, since the voltage would remain the same, given the meanwell is adjusted properly?
I think the voltage range was given for the entire line of LED's, not one specific color/bin, its not from the data sheet, just from the advertisement.
I also have a question about the soldering iron tip. I got a weller 40 watt adjustable iron, and it came with a flat tip. I have been practicing soldering pretinned wire to pennies, but I am thinking there is a better tip I could use, any recommendations for the proper tip for soldering led stars?
I think the voltage range was given for the entire line of LED's, not one specific color/bin, its not from the data sheet, just from the advertisement.
I also have a question about the soldering iron tip. I got a weller 40 watt adjustable iron, and it came with a flat tip. I have been practicing soldering pretinned wire to pennies, but I am thinking there is a better tip I could use, any recommendations for the proper tip for soldering led stars?
ReefEnabler
Premium Member
Hey Guys,
A bit of a more random electrical question for anybody who's up for it.
I have some power hungry 12vdc fans, so I bought what I thought was a good regulated power supply. It puts out 12vdc up to 6a. It's for a laptop.
When I test the output, it's very close to 12, around 12.2a.
So I wired the output of the power supply to a 10k linear pot. Connected one side to (-), the other side to (+), and use the (-) side and the wiper to connect to the fan side. I was hoping to use the Pot to dial the speed of the fans back if they were loud.
But when I test the voltage across my wiper pin and (-) with the pot fully cranked, I am only seeing around 10.4v.. turning the pot lower does bring the value down to 0. My fans won't start with 10v.
Can anybody think why the pot would be sucking up almost 2v off the top? Does that mean my power supply just doesn't like having a pot regulate it, or did I wire something wrong?
A bit of a more random electrical question for anybody who's up for it.
I have some power hungry 12vdc fans, so I bought what I thought was a good regulated power supply. It puts out 12vdc up to 6a. It's for a laptop.
When I test the output, it's very close to 12, around 12.2a.
So I wired the output of the power supply to a 10k linear pot. Connected one side to (-), the other side to (+), and use the (-) side and the wiper to connect to the fan side. I was hoping to use the Pot to dial the speed of the fans back if they were loud.
But when I test the voltage across my wiper pin and (-) with the pot fully cranked, I am only seeing around 10.4v.. turning the pot lower does bring the value down to 0. My fans won't start with 10v.
Can anybody think why the pot would be sucking up almost 2v off the top? Does that mean my power supply just doesn't like having a pot regulate it, or did I wire something wrong?
brassmonkyballs
BMB
does the PS drive the fans when not connect through the pot? Its usually starting current or lack thereof that prevents the fan from starting. You might want to check the resistance of your pot at each extreme
D5HP
New member
Anyone used this big badass driver?
http://www.jameco.com/webapp/wcs/st...2109051&productId=2109051&keyCode=WSF&CID=GMC
I want to run 96 LEDs on it.
http://www.jameco.com/webapp/wcs/st...2109051&productId=2109051&keyCode=WSF&CID=GMC
I want to run 96 LEDs on it.
kcress
New member
Someone should turn you into the SPCP!
I would not expect that to work. The pot is too much resistance even in it's high state. That is why the 10V not 12V too.
I'd suggest you buy a computer fan speed controller. Some are PWM gizmos that also don't dump a ton of heat. They also tend to be open for cooling unlike regular pots.
Please, check my plan:
Top view
tank dimensions: 30"x 24"x 17"(H), mixed reef; SPS corals are at 4-8" under the water line.
I want to keep it as easy and cheap as possible so I'll use only 700mA Constant current drivers and Cree XP-E/XP-G LEDs with 55-60° optics.
Three rows, each with four clusters (36 LEDs total, with the same two heat-sinks), is my second choice, but I'm not sure it will be enough?
Top view
tank dimensions: 30"x 24"x 17"(H), mixed reef; SPS corals are at 4-8" under the water line.
I want to keep it as easy and cheap as possible so I'll use only 700mA Constant current drivers and Cree XP-E/XP-G LEDs with 55-60° optics.
Three rows, each with four clusters (36 LEDs total, with the same two heat-sinks), is my second choice, but I'm not sure it will be enough?
jkopp36
New member
I have one that I'll be running 84 XPEs with. What LEDs and how do you plan to string them?
D5HP
New member
The Satis 3W.
I'd run 6 parallel strands of 16 LEDs. Each would be identical.
If I don't do that I'm going to use like 120-140 of their 1W LEDs over my 75g FOWLR.
I just want better coloration and a FULL light over the tank instead of two single PC bulbs.
Plus this way I can add an anemone for the skunk clownfish pair.
Thoughts?
What degree optics should I use?
I'm thinking 60 degrees for the 3W or 25 degree for the 1W since I'll have about twice as many.
jkopp36
New member
Where can I find the specs for these?
D5HP
New member
I'm hoping to drive the LEDs right over 3.3V...how realistic is that? Well I'll have to get some of the satis LEDs in my hand to figure it out.
Worst case I can drop it back to 15 total per string and still run 90 total.
Another option I'm considering is using one 120W for blue LEDs and an 80W driver for the whites and going with 1W LEDs...so I could just get a TON of them on there.
I have a pretty weird idea for my build I'm really considering.
Instead of using one big honkin' heatsink slab...I'm really thinking about using lots and lots of 4"x1" heatsinks and staggering them around two aquascape islands and angling them down so that very little light is actually being directed at the front glass. I won't even use optics on the lights that are over the rock structure.
This should enable me to get a really uniform light over the whole tank. By using two separate drivers I could slowly ramp up the lights over the day and reach a minimum color temperature of about 10k and then slowly drift back to sunset. This will also let me really knock out the main shadow that is currently caused by my 10" wide glass center brace on the oceanic tank. I want to have 16 LEDs directly over this (maybe more with 1W) and then two more strips of LEDs on adjacent sides with a bit of angle on them such that their beams meet on the sandbed.
I'll get some diagrams up this week to explain this a bit better.
I'd love some input!
D5HP
New member
One more question for everyone....how serious would my heat problems be if I had 4 3W leds running at 700mA on a 4"x1" heatsink with fins?
They would be mounted via allen bolts and arctic silver...not that adhesive stuff.
I plan on having 6 120mm fans with this controlling five of them.
They would be mounted via allen bolts and arctic silver...not that adhesive stuff.
I plan on having 6 120mm fans with this controlling five of them.
brassmonkyballs
BMB
no way to know to be honest. i have experience with similar LEDs from FEDY mounted on a solid sink profile from heatsinkusa and without fans running its gets too hot to touch. I have many stories however with people running them on aluminum channel without fans and they are fine. It comes down to density of LEDs on the heatsink and how hard you drive them.
In my case I have 20 FEDYs and 10 Cree RB on a 5.88 x 15 heatsink. With just the fedys and no cree on it gets too hot to touch when driven at 700ma. Not counting the Cree that works out to 1 LED per 4.41" and it gets too hot to touch....In practice I have the Fedys dimmed less than 50% and the Cree at about 80% and its warm.
I have several tanks and my experience is that my large fixture over my 120 is all Cree and there is no heat running them where i do. My other 2 tanks have Fedy mixed with Cree and fans are mandatory. However, others experience varies.
My Fedys run 3.4v when driven at 700ma. I would expect your satis to be similar....but I recommend you drive them less than 700ma.
D5HP
New member
Thanks a lot for all that.
I'm actually really considering going with 100+ of the 1W LEDs and doing something a little different.
Does anyone know if I'd have problems keeping an anemone with those? For reference...there will be about 50 LEDs per 14"x14" section on each side of the tank and another 30 or so over the center brace...as a rough estimation.
I know it's massively overkill and I'd run them between 275-325mA to keep them a bit cooler. I want to create a stadium-seating-esque heatsink array that is custom to my rock structures...not just my tank size.
This would allow me to have the heat sink strips a little lower towards the front of the tank and use optics. The heat sink would be slightly tilted to aim the LEDs down towards the bottom of the rock structure and away from the front glass.
This should not only eliminate a bit of algae on the front glass but I'm hoping it will make the whole tank appear to be lit completely evenly.
I am building a wood canopy for the tank that will be a skeleton of sorts. The actual LED assembly will be mounted on a lightweight frame that is attached to drawer sliders inside the hood. This will allow me to slide the entire light assembly back a few inches to open up the glass tops on the tank and feed the fish.
Another goal I have is to make the canopy as thin and low profile as possible. There will four 120mm fans on the top of the hood pulling the hot air out and two on the sides pulling air into the hood.
Does that even make sense?
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