LED Part and Heat

Lsuhunter · Dec 16, 2020

I am considering adding another LED strip to my tank, fluval flex 32.5 with a fluval marine 3.0. Would running 2 fixtures at 50% have more PAR and give off more heat than say 1 light strip at 100%? I am thinking more in terms of heat because my tank has a tight fitting hood but also do not want to sacrifice PAR. I am not looking for anything exact about this specific light and I am sure there might be some sweet spots between 50-100%, but I am curious in the more general aspects of LED lighting. Thanks!

Lsuhunter · Dec 16, 2020

If only I could spell PAR in title..

oreo54 · Dec 17, 2020

Lsuhunter said:
I am considering adding another LED strip to my tank, fluval flex 32.5 with a fluval marine 3.0. Would running 2 fixtures at 50% have more PAR and give off more heat than say 1 light strip at 100%? I am thinking more in terms of heat because my tank has a tight fitting hood but also do not want to sacrifice PAR. I am not looking for anything exact about this specific light and I am sure there might be some sweet spots between 50-100%, but I am curious in the more general aspects of LED lighting. Thanks!

Well good question.. ;)
Only real advice would be to keep in mind that a 50% decrease in average current (PWM dimming only cuts current in an on off fashion, doesn't exactly reduce current ) isn't a 50% decrease in photons since the cooler you run them the more efficient they become. Well more like the more efficient they get the cooler they are.. :)

Bottom line is 2 lights at 50% give out more par than 1 light at 100% so to keep the same par you can reduce the lights below 50%.

As a guess then you can run 2 lights at 40% (2 x 40 = 80% so heat is 20% less) and have the same amount of light as one at 100%
Exactly how low you can go is something that would need to be metered.
Most led heat is "up" w/ little or no IR heating.
Concentrated photons of most any color do impart energy to "stuff" so there is some down heating.. and a lot in a tight beam..think magnifying glass and sunlight.
bigger the diodes (3w vs .5W) the stronger the beam if lensed the same.

Practically speaking in a tightly enclosed setting doubt if 2 vs 1 will make much of a difference but you do gain more surface area to remove heat (still needs somewhere to go) and more light spread.

Apologies for the simplification.