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Old 19-04-2016, 04:22   #1
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Calculating Solar Cable Size.

This has me stumped!

I'm connecting my 4 x Sunpower E327W Solar Panels in a Parallel format to my Outback 80

Total Cable run is 19 m to Outback in Pilothouse

2 panels on Port and 2 on Stbd each connect together (in parallel) for 7 meters each (total 4 cables) before joining together at Aft Mast Conduit for remaining 12 meter run to Outback with 2 cables

How do I calculate realistic load and Cable size(s)?? for above deck two pair and combined 4 panel load for last 12 meters?

Also, what breaker size should I put before and after Outback?

Specs for each Sunpower E 327W
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Old 19-04-2016, 04:40   #2
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Re: Calculating Solar Cable Size.

One tool to make these calculations easier is a calculator to find voltage drop in a cable run. One I use a lot is here Voltage Drop Calculator Genuinedealz.com but there are others.

Starting backwards from the controller to where all the cables join, you have 12M with a total max of 4X6 amps at 55V. For that run using two wires (+ and -) I would go with 6 gauge wire.

Then the runs from each pair of panels back to the mast. This will be half the amperage for 7 meters. For that run I would use 10 gauge.

Another online converter gives 6 gauge = 13.3 mm2, 10 gauge = 5.26 mm2.
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Old 19-04-2016, 04:42   #3
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Re: Calculating Solar Cable Size.

Wire Sizing Charts - Affordable Solar

Found this doing a web search. Seems pretty clear and explains how to apply tables to different voltages.
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