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Need Help with DIY Solar Panel Setup for Current Prep Situation

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  • Need Help with DIY Solar Panel Setup for Current Prep Situation

    TLDR: With current resources available, how can I setup these panels (parallel, series/string, and how many, etc)? And are my components ok for now (or should I add/exchange)?

    I'm working on a solar panel setup for my families house that wont be grid tied in right now. Maybe later once situation with Covid19 clears up and it would be easier to get right supplies and permitting setup with city. I purchase the solar panels new locally (which I rather not return) and ordered other components from Amazon and Home Depot (which can be returned/exchanged). Let me list out what I have:

    2 @ BestEquip 60A MPPT Solar Charge Controller Auto Battery Regulator PV 150V MAX Input MPPT Charge Controller Finger Touch Interface for Solar Panel and Lithium Battery

    1 @ AIMS Power PWRINV500048W Power Inverter, 5000 Watt Max Continuous Power, 48V, 10000 Watts Peak Surge Power, Modified Sine Wave, Cooling Fan Thermally Controlled, AC Direct Connect Terminal

    4 @ EverStart Maxx Lead Acid Marine & RV Battery, Group Size 29DC

    I was planning to have a 48v system with 5kw and 120/110v AC (ideally would like 240/220 but might be out current budget)

    Here are my questions. I've been researching these like crazy and sites either point to spam, solar company sales sites, or pinterest for some reason.

    - What configuration should I do my panels in, parallel, series/stringed, and how many?
    - What sort of combiner box should I get for above setup?
    - Would I need another charge controller for the setup (I know the ones I do have are not as robust but with logistics/resources slowing down trying to make something work)?
    - Can I ground each panel to the rails (unistruts) and then ground the unistruts to system (combiner box, down other components then to ground) or do/should I run a continuous wire that connects to all panels, rails and then down?

    Once I know this, I can research what gauge of wire I should need as it would give me an idea of W, V, A are going through, was thinking of 10AWG for the DC wires from panels to combiner box and then maybe something thicker from there to inverter. And of course even thicker for battery terminals.

    Thanks in advance.

  • #2
    If you want it to be grid tied initially and the money is burning a hole in your pocket then forget those details and get a grid tie inverter. The string calculator for that inverter will tell you how many to connect in a string and the connections are simple.

    Then track your consumption in kWhrs and after you have seen how efficient using the grid as a battery then you will be able to assess what size battery system you would need. During that process of assessing your loads you could also decide which circuits are essential and you could move some of them to an essential loads panel. Then add a consumption meter to that panel to really understand what your essential needs for battery capacity would be. By that time there will be a lot more AC coupling solutions out there that will allow you to leverage your grid tied system and create a cost effective system. If you are concerned about power outages in the next few years then buy a small generator and run some extension cords to keep some lights and your refrigerator running. Or you could add a generator transfer switch to your essential loads panel.
    9 kW solar. Driving EVs since 2012


    • #3
      My apologies, I initially read the original post as wanting to be grid tied so the above post may be irrelevant. However a grid tie inverter would be less expensive than the parts proposed and would give the OP some good experience and possibly save money along the way. The proposed inverter would only run off extension cords, just like a generator. So if the goal were to be prepared for a blackout then a generator on extension cords would be less expensive.
      9 kW solar. Driving EVs since 2012


      • #4
        Hey thanks for replying... Grid Tie Inverters seem to start at around $1200, though I did read on this inverter mentioned above that arrived yesterday that it can be tied into a sub panel and I can connect some circuits to that subpanel ideally. I am trying to not spend more money right now and would like to do what I can with what I have and the final pieces I would be missing.
        I feel like the last pieces are how to connect all the panels, do I need another charge controller, do I need combiner boxes and once I have an idea about all that, I should be able to come up with other things myself like gauges of wires and how much length, etc.
        Looks like amazon is slow down (or prioritizing medical shipments more during these times) so would like to order what I can soon before logistics go south. thanks again....


        • #5
          Originally posted by jerryv View Post
          Hey thanks for replying... Grid Tie Inverters seem to start at around $1200, though I did read on this inverter mentioned above that arrived yesterday that it can be tied into a sub panel and I can connect some circuits to that subpanel ideally. .....
          You would have to use a transfer switch to tie in any inverter to a sub panel to prevent back feeding the grid during a power outage. That inverter only puts out 120 volts and I don't know the code issues with powering only one of the buss bars on a sub panel.

          Perhaps others who are more knowledgeable about charging Lead Acid batteries will chime in on the wiring issues with regards to the solar panels. I couldn't find the capacity of that battery and you would need that before anyone could give you input about your charging strategy. There are some ratios that have been referred to on several threads. Most of the time when the grid is working you would only need to trickle charge those batteries to compensate for self discharge and keep them full.
          9 kW solar. Driving EVs since 2012


          • #6
            Your proposed system must be kept entirely separate from the grid. I wouldn't hard wire to a breaker panel unless it is something you add now and wire up some well thought out loads.

            With only 4 Group 29 batteries you haven't got much power available and just keeping that large and inefficient of an inverter on 24/7 would put a substantial drain on them even if not powering any loads. You haven't mentioned which, or how many panels you will use but suffice to say you will need a larger battery bank and you really need some true deep cycle batteries. How big a battery bank, well, the way this works is you start with an accurate daily load to determine battery bank size, which will determine your inverter and solar array size.

            As mentioned previously, you might think of installing a genset and transfer switch. That alone will get you through any outages and give you time to really assess your needs and build a proper solar set up. If you have grid power already , your best approach is grid direct and forget the battery based system.
            2.2kw Suntech mono, Classic 200, NEW Trace SW4024