Meanwell LDD driver: for those who want to dim to 0 using Arduino
- Thread starter pwreef
- Start date
jedi I understand that part just fine. 2 scw's and each one running two fans, each one has just under a 1/2 amp (0.47A) split between 2 fans so all it can run for fans are those little tiny 2 inch fans from the computer store, or am I missing some thing here other than the fans I understand the rest of the board.
jedimasterben
LED world domination!
You don't need a large amount of airflow to cool a heatsink down. Most 80-120mm fans use 0.2-0.3A for low-medium speeds, all you need is low. For every ~4x LDD's worth of LEDs you'd want 1-2 fans, so the boards that have both are great.
Rott-
I added two 12V "outputs" to the screw header next to the power inputs. I put them there so 12V & Ground terminals would be accessible for powering an arduino ect.. But here's the thing! If you need more 12V current than an SCW can provide, the 12V "output" terminal can be used as a 12V "input" instead. Just connect your favorite 12V supply and have at it. The fan control circuit will still work correctly, no matter where the 12V comes from. :beer:
You're going to include a small fan in the box for ventilation, correct?
jedimasterben
LED world domination!
So ebay has plenty of SCW05C-12 available (although from Taiwan only), along with -05 and -15, but there aren't any -09, and I would like to run my fans at 9v instead of 12v. Pretty much all of the 'typical' places have them listed, but none in stock and no expected stock, and I contacted one site in the US that has them listed for like $9.49, but the lead time is 4-6 weeks ARO. Meh.
LOL- Taiwan's where I got mine. I found em' on Fleabay and ordered 10. Shipping took forever...................................... 2 months easy.
jedimasterben
LED world domination!
Yeah, I'm trying for the 9v versions, though, which don't exist on ebay. :/
Ligershark
Member
I have been following this thread for a little while now and need some help figuring out what power supply I need. This is only going to be a dimmable accent light, imagine a high end reef brite if you will. For this reason I am running the led's at low milliamps.
I have a 4 driver board I purchased online, along with a coralux storm controller.
I have the following ldd-h drivers/led strings:
1 350ma driver with 2 cree xte royal blue (moonlights)
1 350ma driver with 3 uv led
1 700ma driver with 7 cree xte royal blue
1 700ma driver with 7 cree xte royal blue
It was recommended to me by someone to use a 36v 2amp 72watt power supply.
How did they figure this out? I know it has something to do with forward voltage, amp output, and some other factors. Is there a formula written somewhere for this. I would like to know the actual math that was involved. I have searched in this thread and on reefcentral and cant find it.
Can I get a bigger power supply instead in case I decide to add more leds or more channels and drivers in the future? I know I would have to get a new board but that is not an issue.
My leds are solderless and are screwed into the heatsink so expanding is not an issue.
Sorry in advance if my questions are lacking some common sense.
I have a 4 driver board I purchased online, along with a coralux storm controller.
I have the following ldd-h drivers/led strings:
1 350ma driver with 2 cree xte royal blue (moonlights)
1 350ma driver with 3 uv led
1 700ma driver with 7 cree xte royal blue
1 700ma driver with 7 cree xte royal blue
It was recommended to me by someone to use a 36v 2amp 72watt power supply.
How did they figure this out? I know it has something to do with forward voltage, amp output, and some other factors. Is there a formula written somewhere for this. I would like to know the actual math that was involved. I have searched in this thread and on reefcentral and cant find it.
Can I get a bigger power supply instead in case I decide to add more leds or more channels and drivers in the future? I know I would have to get a new board but that is not an issue.
My leds are solderless and are screwed into the heatsink so expanding is not an issue.
Sorry in advance if my questions are lacking some common sense.
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jedimasterben
LED world domination!
Add up the forward voltage of the largest LED string, and add 3v to it, and that is the minimum voltage needed on the power supply.
Then, take the forward voltage of each string and multiply by the current, and that gets you the total wattage of the LEDs. Add 20% to that number, and that is the minimum wattage of the power supply needed.
Then, take the forward voltage of each string and multiply by the current, and that gets you the total wattage of the LEDs. Add 20% to that number, and that is the minimum wattage of the power supply needed.
Ligershark
Member
does my forward voltage of the led's change because I am running them at less milliamps?
jedimasterben
LED world domination!
By a small amount, yes. Check the datasheets and you'll see the forward voltage vs current curve.
Ligershark
Member
thank you for your quick replies.
LOL- I put an order at SeedStudios for 5 different PcB designs, back on the 14th. United Parcel service just sent me an Email confirming that my order will be delivered tomorrow! 9 days from the order being placed- to delivery. I don't think it could be done any faster than that!:celeb1:
