EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: paulca on May 18, 2020, 08:07:19 am
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I intend to run 5 meters of 12V LED Strip (WS2811) totallying 150 LEDs.
Theoretical max amps will be (150 * 3 * 20mA) / 3 (series leds) = 3 Amps
I'm going to guess that the 12V line could fall as low as 11Volts and as high as 14.40V. I'm going to also guess the LEDs will be fine down to 10 Volt though this might be extreme.
From the power source to the LED start is going to be around 4 meters and the length of the LED strip is 5 meters (unless I trim it).
So my finger in the air was I need cable running 10m with less than 1 Volt drop. A quick online calculator told me this would require 14AWG or 2mm2 cable. This seems to be available in flat twin core, thin wall for automotive cable at reasonable price.
Note due to the low current of the strip - and the unlikely hood of it actually pulling 3Amps - I am only powering it at one end. I include the length of the LED strip PCB in the total length to try and account for the drop along the PCB, although it will not be 14AWG obviously.
I could power it at both ends, it would be about twice the price in cabling though and one more hold drilled in the garage wall.
Do my finger in the air sums sound about right?
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Of course I think 2.5mm twin and earth mains installation cable could turnout cheaper than possibly plated aluminium automotive cable.