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Dual Battery Fuse/Breaker Layout

Discussion in '3rd Gen. Tacomas (2016+)' started by RedZeppelin, Jan 28, 2020.

  1. Jan 28, 2020 at 7:17 PM
    #1
    RedZeppelin

    RedZeppelin [OP] Well-Known Member

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    So I'm in progress on doing electrical work and wanted to get a sanity check. Here's what I'm planning to do when everything is said and done, please don't judge me this took roughly 200 hours in MS Paint:

    diagram.jpg

    The green boxes are circuit breakers and brown are MRBF terminal fuses. I'm not sure entirely about the orientation of the breakers. Since I'm planning on using the SBI-12D isolator the current can flow both ways, and therefore I'm guessing that the position of the breaker studs are important. For this breaker https://www.amazon.com/dp/B01G2JMEUQ there is an AUX side and a BATT side. Would it be correct to have the AUX side wired to the battery terminal, and the BATT side wired to the isolator?

    And it would follow that a 150A breaker for the SP 9100 would have the AUX side wired to the SP positive post and the BATT side wired directly to the house battery positive terminal.

    Finally, can I have all the negative leads attached to the negative bus and then have one wire going to the negative post of the main battery? Or is it better to have separate leads for the various components?

    Thanks all
     
  2. Jan 28, 2020 at 7:23 PM
    #2
    Cudgel

    Cudgel “Tonka”

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    Yes isolators should be in the correct orientation.
    I don’t know your loads so can’t comment on the sizing.
    Be sure to add up all your loads to calculate the size of the negative.
     
  3. Jan 28, 2020 at 9:49 PM
    #3
    Mokanic

    Mokanic Well-Known Member

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    200 hours well spent. Looks good. Can't answer your questions, but I like how you think on simplifying the components.
    I draw on paper and then I use Word to get similar results. It has pre-defined shapes (lines/arrows/rectangles/circles/elipses, etc.)
    And the drawings are printed out so I can go back to later and remember what I did.
    I may have to try Paint and see how that goes next time.
    Some of the drawings that I see on here and elsewhere have too much or too little information for my taste.
    Or the drawing loses me about halfway through and they don't translate to printing out on a simple page.
    This looks simple, yet effective.:thumbsup:
     
  4. Jan 29, 2020 at 7:02 AM
    #4
    caribe makaira

    caribe makaira Well-Known Member

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    You are missing the generator power input...in the drawing.

    Also:
    upload_2020-1-29_11-19-40.jpg

    Why do you have an additional isolator?
     
    Last edited: Jan 29, 2020
  5. Jan 29, 2020 at 11:51 AM
    #5
    RedZeppelin

    RedZeppelin [OP] Well-Known Member

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    The alternator is part of this, I just didn't include a direct connection in the diagram. The SBI-12D is for a manual override to link the two batteries together in case of a dead starter.
     
  6. Jan 29, 2020 at 11:59 AM
    #6
    caribe makaira

    caribe makaira Well-Known Member

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    SP 9100 breaker should be lower:
    upload_2020-1-29_15-59-4.jpg
     
  7. Jan 29, 2020 at 12:11 PM
    #7
    RedZeppelin

    RedZeppelin [OP] Well-Known Member

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    I've also seen that the SP 9100 has internal MOSFET protections so it might not even need a breaker. I'd even be fine carrying a spare 125A fuse for the power cable
     

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