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Changing wiring on batteries to make room for whizbangjr a few questions

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  • Changing wiring on batteries to make room for whizbangjr a few questions

    Forgive the bad drawing it is not my strong point. My batteries the way I have them hooked up now have been really good at keeping an even charge across the batteries. I am about prepping the wiring to get ready for the whizbang jr and will be putting the shunt in so all will be ready. My question is does is matter where i hook the CC and inverter up inline. I understand those have to be between tied in the same spot but what would be the best place to hook them. I would like to bring the shunt in the garage on the wall but then the CC/inverter negative would also be inside and not connected on the middle of the cable connecting batteries as you can see from pic.

    Is there a better way to wire is it not gonna matter to much.

    Hope this made sense.

    Just so you know yes all the wires com through the house to the CC and inverter in the same whole picture is a bad one but you get the point

    Wiring..jpg

  • #2
    The best place for the shunt is always on the negative battery terminal when you have only one series string.
    When you have parallel batteries it gets difficult with several negative wires running to a common point or bus bar.

    Ideally you should bring the battery negatives all together on one bus bar or terminal bolt and then put the shunt between that point and both your CC and your inverter connection. Just connecting both to the other end of the shunt should work if you can make the connections safely and securely.

    You want the shunt as close to the batteries as possible to minimize the voltage drop in the wiring to the shunt. You only run small wires from the WBJ to your CC.
    SunnyBoy 3000 US, 18 BP Solar 175B panels.

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    • #3
      It just hit me. Thanks I see what you are saying. Disregard last post. Erased.

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      • #4
        One more quick question if I can. I cannot press 2/0 wire. I can solder very well. Would that be ok? We do AC wiring solder all the time is DC any different. We don't do alot of high current DC.

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        • #5
          Originally posted by Stix View Post
          One more quick question if I can. I cannot press 2/0 wire. I can solder very well. Would that be ok? We do AC wiring solder all the time is DC any different. We don't do alot of high current DC.
          The NEC does not allow solder to be the sole mechanical strength of the connection. You need to use a crimp of set screw terminal.
          If you do not want to pay for the needed press tool and dies, you may be able to get a local battery, marine or welding shop to make the crimp terminations for you.
          SunnyBoy 3000 US, 18 BP Solar 175B panels.

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          • #6
            Originally posted by inetdog View Post
            The NEC does not allow solder to be the sole mechanical strength of the connection. You need to use a crimp of set screw terminal.
            If you do not want to pay for the needed press tool and dies, you may be able to get a local battery, marine or welding shop to make the crimp terminations for you.
            Thanks we do have a guy that does the pressing. We trade work but was trying to save a step. Sorry for all the silly questions. DC is a different realm when it comes to high amperage as we do not do alot of it.

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            • #7
              Originally posted by Stix View Post
              Thanks we do have a guy that does the pressing. We trade work but was trying to save a step. Sorry for all the silly questions. DC is a different realm when it comes to high amperage as we do not do alot of it.
              The biggest differences between DC and AC, both at high current is that:
              1. DC arcs are a lot harder to extinguish, since the current does not go through zero 120 times per second.
              2. A non contact voltage tester is useless.

              PS: It is a small point except with very large cable, but there is no skin effect or inductive voltage drop with DC, so the voltage drop on a given length of 4/0 wire or larger can be significantly lower than for 60Hz AC on the same wire.
              Last edited by inetdog; 06-29-2015, 08:17 PM. Reason: PS:
              SunnyBoy 3000 US, 18 BP Solar 175B panels.

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              • #8
                Thanks for the reply. I understand **

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                • #9
                  Hope I do not come off as dense. We do alot of AC wiring. I just never have done a lot of high amperage DC as the wiring is usually done for us. Furnaces and A/C units come prewired. I change A/C to D/C but they provide what is needed. But it is simple things like blower motors and compressors for residential. I feel ignorant coming here and asking these silly questions so bear with me.

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                  • #10
                    No problem
                    Solar and DC is a different animal all together. And although the tech is very old it is something that is rare to come across today outside of electronics and semi conductor type folks
                    Last edited by Naptown; 06-29-2015, 11:12 PM. Reason: Corrected spilling
                    NABCEP certified Technical Sales Professional

                    [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

                    [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

                    [URL="http://www.gaisma.com"]www.gaisma.com[/URL]

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                    • #11
                      Thanks. Going from doing it all yourself to asking people for help is a humbling thing. Embarrassing thing but... Things I need to know.

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                      • #12
                        Originally posted by Stix View Post
                        Thanks. Going from doing it all yourself to asking people for help is a humbling thing. Embarrassing thing but... Things I need to know.
                        That realization is the first part of wisdom.
                        SunnyBoy 3000 US, 18 BP Solar 175B panels.

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