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  • Re-wiring my solar

    Hi,
    I'm new to this forum and looking for some info when I rewire my solar on my trailer. I am just now "getting" how solar works. I've not really done anything solar other than accept what was sold to me. I have the following:
    1. 2015 CreekSide 20fq. 24' tongue to bumper
    2. Came pre wired from factory with a collector box type thing on the roof. #8ga wire from the controller location to the batteries
    3. Dealer installed 2-150w Samlex Polychrystaline type panels running the kit supplied 12ga PV wiring to the controller. The dealer bypassed the factory collector box on the roof and slid them under the mounting flange of the factory installed collector and gooped it.
    4. All this was collected at the Samlex 30a controller which is about 8' of 8ga. wire away from the batteries
    5. All hooked up to 4 each 6v in series then paralleled
    6. The system works if all is good and all our ducks are in straight row. But I think there are many efficiencies to be gained by moving an MPPT controller closer to the battery bank, adding one panel and upsizing all the wiring

    My plan is the following:

    1. Shuffle the panels to allow the installation of a Fantastic Vent over the bed and the addition of 1 each 150w panel to yield a total 450w.
    2. Use #10 conductor form the panels to the new weather proof residential type J-box(remove the existing factory installed collector) Run #8 PV conductor from the J-Box to the new controller location
    3. Install a new MPPT type controller within 4' of the battery bank.
    4 Use #4 wire from the output side of the controller to the Battery Bank
    5. I plan to use the existing 8ga wire that was installed as Battery Charge wire as P.V. to the new controller location. It is easily accessed at the new location of the controller and where I'd need to splice it to the new 8ga. wire coming from the J-Box.
    6. When I install the new J-Box for the PV wiring collection on the roof, is there any reason I can't just use a standard type of hard plastic/baka-lite type electrical connection block in the J-Box? I think it would simplify the in/out, gathering and consolidation of the P.V. conductors on the way to the controller
    7. I've not made up my mind on a controller yet, but I'm bending toward a 60a MPPT type as it would be plenty large............and mot importantly it accepts the size wire I want to use!

    Please let me know your thoughts

    V465

  • #2
    This has sat idle for a while, because no body wants to touch it. I'll give you the guidelines that apply to MPPT upgrades

    Adding more panels, for parallel wiring, they should be within 10% + - of the other panels VOLTAGE For series panels, + - 10% of the AMPS rating

    For MPPT on a 12V battery, your panel array should be about 35VMP ( volts max power) as indicated on the panel sticker. This higher voltage is what allows the MPPT circuit to track and convert the voltage to amps. This can be a single panel with the >35Vmp or 2 panels in series to obtain >35Vmp

    Roof top panels in series should not experience any shading from antennas, vents, railings..... Any shade reduces the voltage in 8V steps and the MPPT stops working

    Roof penetrations in an RV don't really have code, it's all your stuff inside thats going to get wet from spots where the dealer didn't goop it well.

    Exterior wire connections should be done inside a weatherproof box, electrical grade PVC or metal boxes are acceptable. Bakelite is not usually used.

    PV combiners are handy if breakers are used, and are accessible to troubleshoot array issues. Fused combiners are often touted as "touch safe" but are not able to interrupt a circuit under load without destroying the holder from a DC arc. Costs more, but you recoup that cost with reduced labor and simplified troubleshooting in 4 years. ( hey, it's PV array #2 has no power, #1 is just fine)

    MPPT controllers generate some heat, and need cooling air, buried under clothing in a closet won't work for long

    MPPT controllers output higher current than their input, so heavy $$ #6 gauge wire is run from controller to batteries. You use light gauge (#10) wire from panels to controller and it's easier to wrangle through the roof.

    Properly oriented panels only produce 80% of spec amps, less on hot days & less if not optimally oriented (flat on a roof is not optimum). 300w from your 450w of panels would be outstanding, 200- 250w is what I'd expect on a daily basis. That would be more than you obtain now.






    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


    • #3
      Thanks!
      That's a bunch of great info. My main question, which has actually been addressed elsewhere, is regarding the use of traditional use of solder-less connectors and maybe a bus-bar in the combiner box as apposed to the MC4 type connectors and splitters/combiners. I plan on running a UV grade #10 wire form the panels to the combiner box likely in a conduit for additional protection and ease of replacement. Then combining in the J-box on the roof with solder-less connectors and a terminal block, then conventional #8 wire to the controller and #4 or #2 wire to the batteries. How do you like the Morning Star 60a controller?

      Comment


      • #4
        Solderless connectors are not used in solar applications, CRIMP connectors, applied with proper tools are used.

        Solderless connectors are signal level control wires in a ribbon cable - usually called IDC connectors. They are not rated for power. If you walk into a electrical store and ask for solderless, who knows what you get. Ask for UL listed Crimp connectors, and you get the right gear, because you used the right name.

        terminal block is also a world of unknown. Is that the screw terminal barrier strip for ring lugs ? Or a 10 position screw buss bar? IDK what that is.

        I have 2 of the MS-TS-MPPT-60 controllers and love them both. The 60A model has the web interface
        Last edited by Mike90250; 12-07-2018, 09:34 PM.
        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


        • #5
          I'm thinking what I call a "solder-less connector" and what you're referring to as a crimp connector are the same. My dad always called crimp connectors solder-less connectors as he came from the days when everything was soldered and if it wasn't soldered, it was solder-less. Terminal block........a place where on one side I terminate/gather the #10 wires from the panels and on the other side(or same side) a single #8 goes to the Controller. Basically a combiner block with all the #10's coming in and the #8 going out. Chances are, I won't be asking anyone at a store for this or that by name and expecting them to hand me what I need. More by description to get what I need. Long as what ever I get is good for a higher voltage than what I need I should be good. I think my question should have been: Is any 600v crimp connection acceptable to use in place of the MC4 type solar connector.

          Again,
          Thanks for all the help.

          Comment


          • #6
            The MC4 connectors are supposed to be weather tight, and when pre-installed on panels, they make for easy connections. If you only have a couple connections to make, it's better to simply buy some MC4 extension cables, and cut them in half - and voil
            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

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