The Planted Tank Forum - View Single Post - Looking for advice on DIY LEDs
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post #3 of (permalink) Old 02-01-2015, 03:46 PM Thread Starter
MrSpiffy
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Jeffkrol, thanks very much for putting all of that together for me. That's definitely helping me get a grasp on things.

From the looks of it, this basically summarizes what your telling me:

If a PSU is 25V and a single LED is only 11V and 1000mW, I'll need something in the circuit to dissipate the excess voltage properly. (Which would be very inefficient, dissipating 14W on that circuit...)

The driver specs do indicate the capability of power dissipation, to some degree. But the ones from Steve's LEDs only state they'll dissipate 3W per driver chip, with a good heatsink. Only going up a single 11V LED would be a poor choice. I'd need a large resistor, and waste a lot of power.

Does that cover things? I'm sure there's more to it, but basically I need to utilize the fill voltage of the line, minus what the driver will dissipate safely?

If that's true, I may do two 11V LEDs on a single driver to maximize efficiency of the circuit. (And adjust the PSU to lower voltage.) But I need to decide if I really want a pendant system, or would a linear array be the better option.

As for the Arduino, I know I could just pick up the Typhon. But tinkering is part of the project for me. It'll give me something to get into and play with.

EDIT: I noticed the specs on Steve's page display information for both 1000mA and 700mA. Is one preferred over the other? Will driving at 1000mA shorten the life of the LED, even though it's rated for it? (I saw that PWM doesn't actually change current levels, it just switches on and off at a certain frequency and duration to create the effect of dimming.)
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