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profdant139's avatar
profdant139
Explorer II
Apr 06, 2022

Break-even point between cable length and voltage drop?

I have two cables for my portable solar panel – one is 40 feet long, and the other is 70 feet long. (We boondock, and we like to park the trailer in deep shade and put the panel out in the open sun.)...
MNRon's avatar
MNRon
Explorer
Apr 06, 2022
10ga wire is approximately 1 ohm/1000ft. So if the panels try to push 7A, that would be a ~0.5v drop from panel to battery (70ft x 0.001ohm/ft x 7A). The 40ft cable will be ~0.3v drop at 7A. As others have said, sun position will be more important than the difference between these.

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