I got a bunch of LM317s kicking around, but wasn't planning on using them.
I figured resistors would do the job as long as I will willing to do a 200 hour array break-in and readjust resistance if needed. I am also going to have a couple of panel current meters monitoring 6 arrays each. I am also going to have a couple more meters where I can spot check current to individual arrays.

Does an electronic regulator have about the same power loss as a resistor?

Also, I figured using 24 volt power supply is better then using a lower voltage since any power supply voltage variation is distributed across a larger number of LEDs.

I was trying to find info on how large arrays are set up in the sign industry, but could find very little on the web.

I don't know how to calculate thermal efficiency (yet), so I have another question. I figured mounting bare emitters directly to the heat sink is preferable to stars, since you eliminate an extra thermal barrier. But you need to use an adhesive instead of a grease which cuts down a bit on thermal efficiency. Any thoughts on best way to go...stars or emitters?



I am getting ready to start constructing the individual modules. I will run the design specs by you for criticism before I start inhaling solder fumes.

I am going with 10 to 12 watt arrays. so will be running around .5 amp. I am going to try and keep the resistor around the .5v to 1.5v drop range. Do you think this will provide adequate secondary regulation? I hate to see it eating up more then 10% of the power.