DIY Supplemental Led's

[0coool]

So I happen to have a 12v 3 amp laptop power supply driving 2 fans on my t5 lights, call it .75 amp draw to be safe. I'd like to add 2 10-20watt cob royal blue led's to act as moonlights and also add some extra blue color during the daytime. My whole tank runs on an arduino so I have 0-5v pwm available to handle the dimming throughout the day.

Are there any inexpensive drivers that can work with 0-5v pwm without an op amp?
Can LED's in this range be run with just a heatsink or are cooling fans needed?
Does anybody make a nice housing for each these leds? If not I can make something out of metal.

I was thinking of using these leds http://www.ebay.com/itm/20W-Watt-Blue-High-Power-LED-Light-L-5-48-/161068093664?_trksid=p2047675.l4066


Any help is greatly appreciated I'm pretty new to Led's.

[zachts]

Meanwell LDD drivers work well with PWM from Arduino. However you only have a 12 volt supply so your LED needs to have a forward voltage of 9 volts or less to use the LDD driver.


Search around and read thru a few of the DIY LED threads to get a little more background on working with them.

those LEDs you linked will not work on your power supply. You could use a string of 3 x 3watt leds on an LDD driver though.

[Kairus]

I run 2 50w and 2 30w chips from the same seller you linked, they're pretty nice. The forward voltage on those 20w ones are 30v, so they're out of the question for the 12v supply you have. These (http://www.ebay.com/itm/1pc-10W-10-Watt-Royal-Blue-High-Power-LED-beads-Light-Lamp-Chip-450-455NW-/131144581386?pt=LH_DefaultDomain_0&hash=item1e88d3810a) would be fine though. They wouldn't need to be actively cooled, just throw them on a chunk of aluminum in a non confined spot. There are tons on eBay, like this (http://www.ebay.com/itm/Aluminum-Heatsink-Cooling-150x60x25mm-for-LED-Power-Memory-Chip-IC-Transistor-/121244529328?pt=LH_DefaultDomain_0&hash=item1c3abcb2b0). You could run two of these on this supply, but I would probably dim them just a tad to lower their power usage a bit. Meanwell LDD-1000HW (http://www.ledgroupbuy.com/meanwell-ldd-1000hw-led-driver/) to drive each is all you need.

[0coool]

I run 2 50w and 2 30w chips from the same seller you linked, they're pretty nice. The forward voltage on those 20w ones are 30v, so they're out of the question for the 12v supply you have. These (http://www.ebay.com/itm/1pc-10W-10-Watt-Royal-Blue-High-Power-LED-beads-Light-Lamp-Chip-450-455NW-/131144581386?pt=LH_DefaultDomain_0&hash=item1e88d3810a) would be fine though. They wouldn't need to be actively cooled, just throw them on a chunk of aluminum in a non confined spot. There are tons on eBay, like this (http://www.ebay.com/itm/Aluminum-Heatsink-Cooling-150x60x25mm-for-LED-Power-Memory-Chip-IC-Transistor-/121244529328?pt=LH_DefaultDomain_0&hash=item1c3abcb2b0). You could run two of these on this supply, but I would probably dim them just a tad to lower their power usage a bit. Meanwell LDD-1000HW (http://www.clay-boa.com/meanwell-ldd-1000hw-led-driver/) to drive each is all you need.

Sweet so the max I can drive would be 2 of the 10 watt Leds using 1 Meanwell LDD-1000 H right? Or can I run more 10 watt leds or do I need more drivers? Thank you very much for the help! I'm getting tired of ordering the wrong parts and having extras of stupid little things if you know what I mean.

[Kairus]

Sweet so the max I can drive would be 2 of the 10 watt Leds using 1 Meanwell LDD-1000 H right? Or can I run more 10 watt leds or do I need more drivers? Thank you very much for the help! I'm getting tired of ordering the wrong parts and having extras of stupid little things if you know what I mean.

No, 1 LDD-1000H (HW version has the wires predone, makes things easier) per 10w LED. The 1000H/HW outputs 1A maximum. Each of the 10w LEDs require 1A at 9-11v. The LDD will drop your voltage about 2v so it will be perfectly in range when using the 12V supply you have.

Two LDD-1000HW. One for each LED.

If you want more LEDs you're going to need more drivers, the power supply you described doesn't have enough juice to power more than 2 10w LEDs with those fans running. You still will need an LDD-1000HW for each LED unless you buy constant current power supplies, which will explicitly state that they are CC.

Good news is that 12v DC supplies are cheap! Higher voltage supplies are much less common.

If you have any more questions, send me a PM, I don't get notified when I'm quoted.