Thread: Solar panel to controller wire gauge

  1. #1
    Join Date
    Apr 2008
    Location
    E. Sierras
    Posts
    619

    Question Solar panel to controller wire gauge

    OK, this seems like a huge rookie question, but i need to feel better so help me out please.

    Im installing solar on my Popup Northstar TC650 Slide-in.
    Link to post on my Thread: http://www.expeditionportal.com/foru...0&postcount=43

    AMsolar 100W panel with factory 10/2g 8" leads already on it- says 4mm on it.

    Morningstar MPPT 15A Sunsaver Charge Controller mounted close to battery and fused with 25A breaker.

    I want to use:
    stranded copper cable-
    8g cable from panel to controller - ~15ft. run
    4g cable from controller to battery- 3ft. run

    Is this adequate?

    Sorry, it has prolly been covered a hundred times i just could not find what i was looking for.

    thankyou in advance,
    aaron
    '87 &'10 4runner
    '10 Tundra

  2. #2
    Join Date
    Apr 2008
    Location
    E. Sierras
    Posts
    619
    a conservative calculator- recommends i use 12g all the way for a 25' run.

    http://www.freesunpower.com/wire_calc.php
    '87 &'10 4runner
    '10 Tundra

  3. #3
    Join Date
    Nov 2007
    Location
    West Texas
    Posts
    414
    Quote Originally Posted by zidaro View Post
    OK, this seems like a huge rookie question, but i need to feel better so help me out please.

    Im installing solar on my Popup Northstar TC650 Slide-in.
    Link to post on my Thread: http://www.expeditionportal.com/foru...0&postcount=43

    AMsolar 100W panel with factory 10/2g 8" leads already on it- says 4mm on it.

    Morningstar MPPT 15A Sunsaver Charge Controller mounted close to battery and fused with 25A breaker.

    I want to use:
    stranded copper cable-
    8g cable from panel to controller - ~15ft. run
    4g cable from controller to battery- 3ft. run

    Is this adequate?

    Sorry, it has prolly been covered a hundred times i just could not find what i was looking for.

    thankyou in advance,
    aaron
    That's the way I did mine. I have been running my AMSolar since about 2006.
    Bruce
    '04 Mitsu FUSO FG639 / '04 Casita
    aka:"RoadHippo"
    West Texas
    " 200 miles from everywhere!"

  4. #4
    Join Date
    Apr 2008
    Location
    E. Sierras
    Posts
    619
    4mm = 12g i think.

    BTW- I really am not great at vehicle electronics, trying to learn as I go here.

    Anyone have great ideas/product for penetrating the roof with 2 8g. cables?
    '87 &'10 4runner
    '10 Tundra

  5. #5
    Join Date
    Nov 2007
    Location
    Scottsdale, AZ
    Posts
    1,720
    With #8 @15' you have less then 1% loss at the rated output.
    "Knowledge without experience is just information"--Mark Twain

  6. #6
    You will not regret using 8awg panel to controller and 4awg from controller to battery. I used 12 with a 130 watt panel, and I am kicking myself. It is especially important with MPPT controllers. Also put the controller as close to the batteries as you conveniently can without them sharing the same space.

    Here are some good through the roof products for the wires.
    http://www.mcmaster.com/#catalog/116/825/=940uyv

    I used tinned marine wire and 3m 5200 adhesive sealant through my fiberglass roof. No leaks, but no chance of removal without serious tools.

  7. #7
    Join Date
    Apr 2008
    Location
    E. Sierras
    Posts
    619
    Thanks WRC, i hadnt found those from mcmaster.

    Here are 2 options for roof penetration:

    http://www.defender.com/product.jsp?...467&id=1351907

    http://www.jamestowndistributors.com...o?pid=661&BASE

    [ame="http://www.amazon.com/Ancor-765004-Marine-Electrical-0-Gauge/dp/B000NI01A8/ref=pd_rhf_p_t_3"]Amazon.com: Ancor 765004 Marine Grade Electrical Wire Seal (Round Cable, 1 to 3/0-Gauge, 3/4-Inch NPT, UV Black): Sports & Outdoors[/ame]

    I'm liking the rectangular multi-mount best.

    and thanks for the wire size advice as well, it is making me feel better. Last thing i want is undersizing. but overkill is overkill too.
    '87 &'10 4runner
    '10 Tundra

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