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Old 02/21/2011, 05:31 AM   #64
kcress
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Join Date: Dec 2007
Location: Central California Coast.
Posts: 5,383
Picking up were we left off.
I want to go back a bit and show the fire-up process of a parallel string build.

Once you have everything wired up you need to check your wiring. You should really NEVER turn on a build and have parts of strings not correctly go on. That's really bad form. So the first thing you do is use a DMM with a diode test. Set it to DIODE and run down every single LED. Touch the solder blobs not the other pads. We don't care about the other pads, we only care about the ones we actually used. (Sorry for the hazy pictures the camera focused on my fingers!!)

Here I probe a blue LED in the proper direction and you can see it lights up. If it doesn't you have a problem. You could also do this with the two AA batteries method.



Next I move one probe to the chassis leaving the other in place. If I botched something that shorted the other lead to the chassis the LED will light up again - incorrectly.



Then I go back across the LED to light it up again and swap the opposite probe to the chassis to check for a short on the other side of the LED. Do this on every single LED on your build before powering up. It takes only a few minutes and will prevent any ugly, expensive, surprises.



That done we can move on to adjusting the driver. I turn the current limit allllll the way down. Sometimes they ship them all the way up. If they do this and your strings are badly balanced you could toast one. If you turn it all the way down you likely won't toast anything even with horribly mismatched strings.



Also take the time to turn the voltage limit all the way down too. This is a safety thing that can also save you in a mess up. Large currents tend to require higher voltages. Turning the voltage limit down limits the current that can occur through a secondary aspect.




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