OK, been following along here for awhile and now its time to start a LED build of my own. Have a couple of questions before I get started with my layout.
I plan on using all Cree LED's over a 48" x 18" tank. Layout is in progress but will be working in XT-E Royal Blues, XP-E Blues, XT-E Cool White (have some Neutral whites also), XP-E Reds and Greens.
1. In looking at the Cree data sheet what Vf do you use to figure how many lamps in each series string. The 'Typical' or 'Max' voltage or somewhere in between?
2. If I limit the drive current to say 700ma can I mix the XP-E blues and XT-E RB's in the same string or do they have to be in their own string. Not sure what effect the different forward voltage would have. I would like to control the both blues with their own driver.
Also beside keeping within the voltage and current ratings is there something else I should be looking at for driver selection? I'll be using 1-10 volt control from a Reefkeeper.
Thanks for any help you can give.
For a 0-10v driver, meanwells are the way to go. On an ELN 60-48D, you can have 9 XT-Es. At 700ma, this is 27v, at 1300ma, this is 45v. That is the best way to use them, to their full potential. At 700ma, you can run parellel strings, and put more LEDs on one driver, so if you kept the curent lower, you could use up to 24 XT-Es at 700ma, in strings of 12, wired parellel. At that current, I would reccomend 36 XT-Es for each half of your tank, plus colored LEDs. I would go as followed: 1 driver with 2 strings of 12 royal blues, each string on a different heatsink, one driver with 2 strings of 12 cool whites, 1 string on each heat sink, 1 driver with 1 string of 6 XT-E royal blues, 3 reds, 2 blues, and 1 green, 1 string of 6 XT-E royal blue, 3 reds, 2 blues, 1 green, and 1 driver with 2 strings of 12, each one with 3 cool white XT-Es, 1 warm white XT-E, 2 neutral white XT-E, 3 blues, 3 greens (or maybe more reds if you want). Each driver will have one string on one 18" heat sink, and the other on the other 18" heat sink for the other side of your tank. Also, you can use another meanwell to add up to 24 420nm violet LEDs, I would add 12, 6 on each heatsink (not wired parellel). There are bigger drivers that you can use to have more XT-Es, and run them at a higher amperage, which is what I reccomend. The strings I suggested above were meant to be driven at 700ma, and the violets at 650ma. GL with your project!
