Underpowering an LED strip

wellsi

Active Member
Just after anyone's experience on under-powering LED strips. I have a 120w 24v transformer and would like to power a 10m 5050 RGB 24v strip that has 60 leds / m.

Assuming 0.25w per LED, that's 600 x 0.25 = 150 watts. Will I ruin the LEDs if I only supply 120w? Having them a bit dim is fine. I'm assuming I can't overload the transformer as it will ony give out what it can.... but any advice welcome.

Cheers
Ian
 

supraTTman

Banned
Wrong assumption!!

In theory, 2 off 60/m strips will need 14.4W/m x 10m = 144W running flat out = all R G & B LED's ON = bright white, so you are not far out on that score.

Running a switched mode power supply higher than around 80% of its rating will reduce the lifetime as it is working quite hard even at 80%.

So in theory you will need 144W/0.8 = 180W for good reliability.
 

wellsi

Active Member
Fair enough! Thanks for the advice!

Cheers
Ian
 

Member 721023

Novice Member
I would also like to add a tip; usually more than 150 Watt chassis PSU will have a built-in fan and that will cause some noise that could be disturbing if installed in silent enviroment. For this reason I would suggest an enclosed switch mode PSU (IP67) not less than 180W as very correctly already suggested to you.
 
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supraTTman

Banned
Good point Hiline, I have found with my several psu suppliers that the threshold between fan-less psu's and fanned psu's to be around 20A/12V = 240W or 10A/24V =240W same power factor.
 

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