Anyone willing to review my 12V DC system design?

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  • TheMokasin
    Junior Member
    • Jul 2021
    • 4
    #1

    Anyone willing to review my 12V DC system design?

    Hello - I'm new here. Thank you in advance for checking out my post.
    Although I have some general knowledge of electronics (engineering background) this is all VERY much new to me.

    I am converting a van (econoline 150 base) and it will be outfitted with a very modest 100w solar setup (alongside a 20A DC to DC charger).
    The system will be 12V DC ONLY and not be supporting very many components. (12V fridge, a couple outlets, a couple LED lights and fan).
    The system will be anchored by a 200Ah AGM battery and will travel mainly in southern California.

    I realize time is our most precious resource, therefore I am extremely grateful for any feedback anyone can provide on the attached diagram.

    Lastly - One QUESTION I'm not sure about is;
    Assuming the starter battery is sufficiently grounded to the chassis, is that sufficient ground for the entire system?
    (The starter battery will be connected to the system via the DC to DC charger)

    Thank you so much and I look forward to any input! ​​​​​​​

    Quick Note about the diagram:
    - Pictures (pretty much) represent the actual hardware I purchased
    - Yes, I went on a little Renogy shopping spree
    - Some wire text is in red, only indicating to myself that they have not been purchased yet

    Latest Wiring v3_20210827.PNG
    Tags: battery, diy, newbie, solar panels, wiring
    • chrisski
      Solar Fanatic
      • May 2020
      • 553
      #2
      It looks pretty good.

      A MRBF fuse may not be a good choice for a main battery fuse. I like lithium because of the high possibility of delivering huge amounts of amps. Because of the possibility, a fuse rated high for

      Please don't use the breakers you have listed if these are audio or unbranded. Those do not hold up well for solar installs. I like DC midnitesolar circuit breaker.

      For the SCC fuse, you could make that a midnite solar C/B also and put that inside the same box. The midnite solar circuit breakers can be turned on and off just fine.

      You definitely have an audio circuit breaker pictured between the starter battery and Dc to Dc charger. This needs to go. This is not a lithium battery so something besides a class T fuse could go in, but a quality fuse.

      I do not see a inverter, but I see outlets listed. If these are AC outlets, the power requirements need to be re-looked. 1800 watts is around 15 amps at 120 volts, but when pulled from a 12 volt battery from an inverter can change to 2000 watts and 155 amps at the lower voltage. That changes things considerably. If this is strictly a DC build, it applies not at all.

        Comment

        • TheMokasin
          Junior Member
          • Jul 2021
          • 4
          #3
          Originally posted by chrisski
          It looks pretty good.

          A MRBF fuse may not be a good choice for a main battery fuse. I like lithium because of the high possibility of delivering huge amounts of amps. Because of the possibility, a fuse rated high for

          Please don't use the breakers you have listed if these are audio or unbranded. Those do not hold up well for solar installs. I like DC midnitesolar circuit breaker.

          For the SCC fuse, you could make that a midnite solar C/B also and put that inside the same box. The midnite solar circuit breakers can be turned on and off just fine.

          You definitely have an audio circuit breaker pictured between the starter battery and Dc to Dc charger. This needs to go. This is not a lithium battery so something besides a class T fuse could go in, but a quality fuse.
          Thank you for the feedback chrisski! Upon further review, I agree that using amazon reviews to select a "good" breaker is likely a mistake.
          That said, I really do not want to use a breaker panel for several reasons. Do you think the surface mount style breakers are ok if I used a more reputable brand? Blue Sea perhaps? These seem popular in many van builds.

          Regarding the audio fuse between the starter batt and DC-DC. I chose this because it seemed like the most reasonable thing that I could mount inside the engine bay (to stay close to the battery). Do you have a different recommendation for this application? Thanks again!

            Comment

            • Mike90250
              Moderator
              • May 2009
              • 16020
              #4
              You need to investigate your fridge, is it a Compressor based or a Absorption based ?
              I just discovered my absorption fridge consumes about 4kwh daily, in the summer - ok for now, but untenable in the winter with less sun and long nights
              Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
              || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
              || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

              solar: http://tinyurl.com/LMR-Solar
              gen: http://tinyurl.com/LMR-Lister

                Comment

                • TheMokasin
                  Junior Member
                  • Jul 2021
                  • 4
                  #5
                  Originally posted by Mike90250
                  You need to investigate your fridge, is it a Compressor based or a Absorption based ?
                  I just discovered my absorption fridge consumes about 4kwh daily, in the summer - ok for now, but untenable in the winter with less sun and long nights
                  Thanks Mike! I haven't pulled the trigger on the fridge yet, but it will be a compressor when I do.

                  Also - I should've stated this in the original post. This vehicle will be strictly weekend warrior stuff. Def not full time vanlife.

                    Comment

                    • chrisski
                      Solar Fanatic
                      • May 2020
                      • 553
                      #6
                      Originally posted by TheMokasin

                      Thank you for the feedback chrisski! Upon further review, I agree that using amazon reviews to select a "good" breaker is likely a mistake.
                      That said, I really do not want to use a breaker panel for several reasons. Do you think the surface mount style breakers are ok if I used a more reputable brand? Blue Sea perhaps? These seem popular in many van builds.

                      Regarding the audio fuse between the starter batt and DC-DC. I chose this because it seemed like the most reasonable thing that I could mount inside the engine bay (to stay close to the battery). Do you have a different recommendation for this application? Thanks again!
                      I don’t have experience with the surface mount Blue Sea breakers, but WhenI hear Blue Sea I think Quality. That will meet the specs for what’s listed.

                      For inside the battery bay, any (quality) fuse would do. Maybe a Bladed ATC fuse that could be spliced in or a Mega Fuse and a holder.

                        Comment

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