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Wire reducer? Downsizing 1 AWG for Charge Controller

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  • Wire reducer? Downsizing 1 AWG for Charge Controller

    I have a pair of 120 watt panels on my RV (soon to be upgraded to three 320 watt panels), so I rewired them recently from my thoroughly inadequate 10 AWG wire to 1 AWG.

    BUT... the terminals on the back of my charge controller (currently a Renogy Adventurer 30A unit) are tiny. Looks like the largest it'll take is 8 or 10 AWG.. so I need a way to reduce the wire size without canceling out the benefit of having gone to the larger cable. I'll do the same thing on the output side of the controller to the batteries.

    The ultimate plan for the near future is to go with the three 320 watt panels, and then eight or more 6v batteries in case anybody is curious. I have a 1000 watt pure sine inverter right now, but will replace it with a 2800 watt unit too. Since I live in this RV fulltime, I want to eliminate my need for shore power perhaps except for when I need A/C. I can run my generator for that.

    Thanks.

    Rob

  • #2
    The two most common ways to deal with your situation are:

    1. Use a suitable connector (probably not just wire nut) to pigtail a short section of 8 AWG wire onto the end of the 1 AWG. The voltage drop will be minimal over that distance and the drop across the connection can be made very small.
    2. Crimp a pin terminal with a small enough diameter to fit the CC onto the end of the wire.
    SunnyBoy 3000 US, 18 BP Solar 175B panels.

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    • #3
      Thanks!

      The pin terminal thing you mention is kinda what I was thinking, if I knew where to find them. We have a local electronics store nearby (not Radio Shack; a real one) but not sure they'd carry something for wire that large. I bought the wire at a welding supply store so it would be nice 'n flexible.

      If the pin terminal idea doesn't work, then your idea of a short 8 AWG would work. What if I soldered it together? I have a nice butane soldering torch so I can get the wire good 'n hot.

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      • #4
        Yes, I have used crimp on pin connectors. Works very well. If you have a proper MPPT controller, you can put your panels in series and run a higher voltage to the CC therefore requiring smaller gauge wire. generally AWG 10 is sufficient.

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        • #5
          If you solder make sure you use shrink tubing to cover the wire and solder connection.

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          • #6
            Don't use solder to make high current connections, If the connection heats up, it melts & falls apart, with molten solder beads going everywhere,
            Either use a split bolt to splice a smaller wire for the final connection, or use a Ferrule Pin of the right gauge.
            http://www.ferrulesdirect.com/Mercha...=NONINSPINTERM
            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

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            • #7
              Crap. Okay, then what's the best way to connect a smaller-gauge wire (e.g. 8) to 1 gauge? And would wire that big really heat up to 500+ deg F to melt the solder? 30A max.

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              • #8
                Originally posted by RobG View Post
                Crap. Okay, then what's the best way to connect a smaller-gauge wire (e.g. 8) to 1 gauge? And would wire that big really heat up to 500+ deg F to melt the solder? 30A max.
                As I said, split bolts (nearly any electrical store) or crimp on a Ferrule to reduce the size right at the connection, you slide the Ferrule in, instead of the stranded wire.

                Don't use a twist on wire nut, they don't always make a great connection, and can overheat with the long duration, continuous current in solar.

                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

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                • #9
                  I've been googling split bolts and wire reducers, and I haven't yet found one that goes from 8 to 1. They only seem to go two steps (e..g. 6 to 8, 4 to 6).

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                  • #10
                    If you use a split bolt it does not mater, just purchase the split bolt for your largest wire and place your smaller wire in the back and torque it down.

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                    • #11
                      There is no justifiable reason to use 1 AWG, even 10 AWG is overkill providing the one-way distance is 15 feet or less. Over 10 feet then 8 AWG.

                      But to answer your question wil require some very expensive tooling to compress either "H" or "C" Taps.





                      You will not be using 6 golf cart batteries with 320 watts of panels. If you do will destroy the batteries from chronic undercharging and stratification. It takes 900 watts of panels to support 6 golf cart batteries. 320 watts is just right for a pair of 6-volt golf cart batteries. Wire your panels in series, use a MPPT controller and life is good. a 320 watt panel wired in series is roughly 10 amps of current from the panels, and if the one-way distance between panels and controlle rif 5 feet or less, 12 AWG is all it takes to meet 2% or less loss. Only thing 1 AWG is cost you a lot of money and buys you NOTHING except trouble like how to terminate it to your controller. .
                      Last edited by Sunking; 10-19-2016, 01:15 PM.
                      MSEE, PE

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