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Old 02-26-2019, 09:06 AM   #1
Mini-Skoolie
 
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Solar cable gauge help!

Hey all,

My girlfriend and I are putting together a 12v 600 watt solar array up on the ol skoolie (insta @bedbusandbeyond) roof but Iím having trouble figuring out what gauge cables to use. Iíve taken a look at a few charts but theyíve seemingly given me contradictory info on voltage drops.

So! Without further ado, here is the fun technical plan: I was thinking of running 3 panels in series and then connecting them in parallel to another 3 panels in series. I think this would result in optimum operatint voltage of 17.8x3= 53.4V and an optimum operating current of 5.62x2= 11.24A. I suppose I could do 3 sets of 2 if necessary.

Right now I have a 20 ft/10 gauge cord to connect my 40 amp charge controller to the panels. I also have a 8 ft/ 10 gauge for the tray cable. Are these wire gauges too small? If I need to get new ones what should I get? I could probably get away with a 10 ft wire instead of a 20 ft.

Thanks!
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Old 02-26-2019, 09:32 AM   #2
Bus Geek
 
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https://www.renogy.com/calculators#tab_solar-cable

Looks like 10 gauge for a 20' run carrying 11.24 amps will keep your voltage drop under 2%.

For the install you lined out 10 gauge will be fine.
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Old 02-27-2019, 12:54 AM   #3
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Reminder, the shorter the run (which is the total to the battery and back) the lower the resistance (and voltage drop) in the cabeles themself. So, unless you expect to have to move the panels and will need the extra length, cut off the excess and run only that which you need to make the run plus just a little slack.
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Old 02-27-2019, 05:38 AM   #4
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10 gauge wire is normally considered to be good for 30 amps. I used 8 gauge because I had it and if I want to add more panels the wiring will support it.

The renogy connecters work with 10 gauge wire.
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Old 02-27-2019, 09:28 AM   #5
Mini-Skoolie
 
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Ah perfect! The windy nation chart scared me, but I guess it didn’t account for my series and parallel connections. Thanks guys! Now I don’t have to buy new wire
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