Some power / light data for LEDs — slightly lower voltages can sharply reduce heat and extend LED life. If you are using a dedicated adjustable power supply, you might not need to use PWM to dim LEDs. Less flicker, less noise.
Michael K Johnson June 14, 2018 17:51
My quick and dirty graph of the data from the article:
Michael K Johnson June 14, 2018 17:56
I don’t have the ability to measure light intensity, but I at least could characterize current by voltage on a white LED strip I found lying around. It’s pretty linear down below 10V for this strip. That’s consistent with the few data points from the article.
Alan Cox June 14, 2018 18:38
Same with incandescents - low voltage dc makes them last vastly longer
Daniel Berrange June 15, 2018 03:00
Interesting info, as I’ve built UV LED light box for alternative photographic printing processes and heat dissipation is the main issue I have, preventing its use for extended printing times. I’ll definitely have a try at dropping the voltage after reading this…
Michael K Johnson July 01, 2018 15:02
I also found that the voltage drop down the strips of LEDs I just installed was so large that feeding 11V from the power supply led to 8.8V on the other end of the furthest strip. Even 12.2V from the power supply dropped 0.2V in about one meter of 18AWG (~1mm) between the power supply and the strip, and was, no surprise, about 10V at the far end of the furthest strip. This was pretty thin stuff. Maybe if I had paid more I could have gotten better strips with thicker copper. :)
Daniel Berrange July 01, 2018 15:16
For my lightbox I cut the 3m length into sections so have five strips in parallel instead which limits voltage drop
Michael K Johnson July 01, 2018 15:19
My application doesn’t allow that. I am using the whole 5M length for each strip, and there isn’t even a good opportunity to feed from both ends.
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