Basic question (again):

I have a LED-strip that requires 5V, and each LED (150 in total) requires about 60 milliamps. Calculating everything, I need 3 of these LED-strips (450 LED in total). This in turn tells me that they require 27 000 milliamps (27 amps), which is about 135W. Which means I need an external power supply to power them. I think about buying a 5V 40A (200 W), which should be sufficient(?).

But, is there any reason that I should not buy anything with more watts (250 or 300)?

Thanks for any help!

  • i would actually rather have 3 different 10A (or 12A for margin) supplies, so that my cables weren't heavy and/or a burn risk.
    – dandavis
    Aug 12 '19 at 19:35

Are you sure every led is 60 mA? Or you mean maybe each Red, green and blue led inside each led (3 x 20 mA).

You always should buy slightly more than you need (but you think about 200W instead of 135W) already which is more than enough safety overhead.

Why would you need more? If you mean to control it with an Arduino Uno, that MCU (including the LEDs etc) is high likely more than a few hundred mA. So the only reason why you need more, is if you want to control later more LED strips, or any motor or other power hungry external devices.

  • Thanks for your reply! Yeah, I meant 20 mA each red, green and blue. Based on what you write it seems fine to go with 200W, so I will try that. Thanks again for making things clear! :)
    – Araw
    Aug 12 '19 at 19:39

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