Cruisers Forum

Join CruisersForum Today

Thread Tools Rate Thread Display Modes
Old 19-04-2016, 03:22   #1
CF Adviser
Pelagic's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Boat: Van Helleman Schooner 65ft StarGazer
Posts: 7,316
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
Attached Thumbnails
Click image for larger version

Name:	1461061323221.jpg
Views:	90
Size:	65.5 KB
ID:	122842  
Pelagic is online now   Reply With Quote
Old 19-04-2016, 03:40   #2
Senior Cruiser
skipmac's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Location: 29 49.16 N 82 25.82 W
Boat: Pearson 422
Posts: 13,003
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 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.
The water is always bluer on the other side of the ocean.
skipmac is offline   Reply With Quote
Old 19-04-2016, 03:42   #3
Registered User

Join Date: Dec 2012
Location: Jacksonville, Florida
Posts: 50
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.
bglad is offline   Reply With Quote

cal, size, solar

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Calculating Diesel Generator Size beebopbogo Electrical: Batteries, Generators & Solar 17 27-04-2015 11:02
Wire Rigging: calculating cable stretch svmariane Deck hardware: Rigging, Sails & Hoisting 0 11-12-2014 16:27
Calculating size generator I need (in Kw) callistov42 Electrical: Batteries, Generators & Solar 14 23-07-2012 18:17
Calculating House Bank DC Fuse size. Pelagic Electrical: Batteries, Generators & Solar 1 28-07-2008 02:05
Calculating Block Load Charlie Construction, Maintenance & Refit 12 27-03-2007 13:57

Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 19:25.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.