Electronics > Projects, Designs, and Technical Stuff
Getting the correct wire guage for 12V/5A LED extension wires
DW1961:
Having a hard time finding this information.
This is for a single color 12V white LED strip using 600 2835 LEDs on a 16' strip..
I just need to extend the wires between the supply/controller about 14 feet one way. I'll use stranded copper wire.
12V max amps will be 5.
Thanks again!
cliffyk:
--- Quote from: DW1961 on July 15, 2020, 05:32:28 am ---Having a hard time finding this information.
I just need to extend the wires between the supply/controller about 145 feet one way. I'll use stranded copper wire.
12V max amps will be 5.
Thanks again!
--- End quote ---
It is not practical to pull 12 VDC @ 5 A across 145 ft with any reasonable size wire--even let's say 12 ga. (actually a pretty hefty wire)--at that length he wire's resistance (both directions) would 0.4606 Ω.
Pulling 5 A across that wire would cause a voltage drop of 2.30 V, leaving just 10.7 V for your load,
Using a more manageable wire size, say 18 ga. "doorbell" wire would bump the resistance of the conductors (again in both directions) to 1.85 Ω. The voltage drop at 5 A would be 9.25 V, leaving just 2.75 V for the load.
You need to move the power supply closer to the load.
DW1961:
Crap, mistype. I meant 14 feet. Changed in original post!
Also updated the information for the strip itself.
cliffyk:
--- Quote from: DW1961 on July 15, 2020, 07:11:59 am ---Crap, mistype. I meant 14 feet. Changed in original post!
Also updated the information for the strip itself.
--- End quote ---
Well that's a horse of a different color!
In that case the aforementioned 18 ga. wire would be OK, at 14 ft the resistance (both ways. you have to use "both ways" as the electricity travels both ways) would be just 0.1788 Ω, so the voltage drop at 5 A will be just 0.89 V. Use 16 ga. and it will be just 0.56 V...
cliffyk:
--- Quote from: blueskull on July 15, 2020, 08:29:36 am ---AWG18 copper wires have resistivity of 0.021 Ohms per meter, for 28 feet round trip, it is 0.179 Ohms, so at 5A, you have 0.897V of drop. Not the most efficient way to do things, but it will work.
--- End quote ---
My wife explains to people all the time that when "He says "OK", he means 'marginally acceptable'", not 'Oh boy, it's Miller time!'"...
It's kind of like when I say "I don't care.", she explains that I am not being dismissive or petulant but instead "He doesn't really give a crap."
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