I need to run 12v across 30 feet of 18 guage wire. The device on the other end consumes 2 amps.
I have a 12v power supply (rated 3A) and I want to ensure the device on the other end gets the full 12v.
I found this post voltage loss calculation but I'm not clear on something. If my power supply can put out 3A and the device only needs 2A, does that mean there will be no voltage loss? (there is no sense wire) Will the full 12v arrive but there will be current loss?
I'm missing something basic here...
I found 18 guage copper wire has resistance of 6.385 Ohm/1000 feet. so 6.385 * 60feet/1000feet * 2 amps = .76v loss.
From the comments it's apparent that voltage loss is unavoidable. So if I need 12v at the other end of the wire, I will need a power supply with 12.76v output (or adjustable). I already purchased a 12v switching power supply from ebay today for $8 - perhaps i bought too soon. Can these power supplies be adjusted (crack open the case)? Do 12v power supplies really put out exactly 12v? (Or do they put out 13v assume loss on wire, etc)