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  • Grounding question

    Hello,

    I need a clarification about grounding. I'm confused about wiring to the same grounding the charge controller (flexmax 80) and the inverter (meanwell 3000w)
    1)is it a problem to wire the ground chassis if both devices to the same wire (in paraller)?

    2)
    Can I ground in parallel the negative Pole of battery bank to the above grounding or isn't it necessary as my system is small?

    3) does the AC output of an inverter needs grounding too or is it grounded already by DC grounding?

    My system consists of:
    24v 300ah battery bank
    Outback flexmax 80 cc
    3000w meanwell inverter

    Thank you in advance
    Last edited by Takis; 06-27-2020, 12:50 PM.

  • #2
    1) Not a problem.
    2) You probably shouldn't ground the negative of the battery but it depends on your inverter.
    3) Yes.

    Comment


    • #3
      Thanks[​​​​​QUOTE=Salts;n416982]
      3) Yes.[/QUOTE]

      does the AC output of an inverter needs grounding too or is it grounded already by DC grounding?

      Is it already grounded?

      Comment


      • #4
        Originally posted by Takis View Post
        Thanks[​​​​​QUOTE=Salts;n416982]
        3) Yes.
        does the AC output of an inverter needs grounding too or is it grounded already by DC grounding?

        Is it already grounded?[/QUOTE]

        The AC side of the inverter must be grounded and bonded to the house and the array. You must put frame grounds on everything and they must all run back to the same point.

        It also doesn't hurt to sink extra earth rods and bond those in as well. The more rods you have in the earth, the better.. but you must have at least one, and if you put more than one, they should all be bonded together electrically or it doesn't count towards the earth grounding. Doesn't hurt, just doesn't count.

        Comment


        • #5
          Originally posted by Takis View Post
          Hello,

          I need a clarification about grounding. I'm confused about wiring to the same grounding the charge controller (flexmax 80) and the inverter (meanwell 3000w)
          1)is it a problem to wire the ground chassis if both devices to the same wire (in paraller)?

          2)
          Can I ground in parallel the negative Pole of battery bank to the above grounding or isn't it necessary as my system is small?

          3) does the AC output of an inverter needs grounding too or is it grounded already by DC grounding?

          My system consists of:
          24v 300ah battery bank
          Outback flexmax 80 cc
          3000w meanwell inverter
          Legally, we don't know what rules apply to your system, fixed, household, mobile and there is so much variability between jurisdictions, you need to either learn the Building Code as applied to your configuration, or hire a local, licensed expert if you are unable to decide.

          You need to know how your inverter wants to be grounded, the controller and what the premise wiring is.

          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


          • #6
            I don't know the rules of fixed or household but it's off grid located in house with separate grounding.

            I've read the inverter manual and doesn't report anything about grounding ac except the attached schema.

            Should the AC ground wire to get grounded?

            I've also attached my setup diagram so far.
            Any help appreciated.
            https://postimg.cc/8svr7fst
            https://postimg.cc/nsshNND0
            Last edited by Takis; 06-28-2020, 03:45 PM.

            Comment


            • #7
              When I see 24 VDC, 300ah battery, and a 3000 watt inverter, I start thinking that that system is way underpowered and a fire hazard. I would think before even thinking about figuring out how to ground the system, you'd want to do some calculations to see about the battery system needed to run the inverter or downsizing the inverter. I'd think maybe you need to go up to 48 VDC, but there's a whole lot of calculations to see how much power you need. There's something like 100,000 electrical fires a year in America, probably more, and I think no amount of grounding is going to fix how overtaxed the system could be. I've had two appliances in the last two years have small flames that were plugged in GFCI outlets, and I think this is because they were just too old.

              I would like to view the diagram, but as a rule, I don't click on links. I've picked up to many viruses that way. Pics can be posted fairly easy.

              Comment


              • #8
                For now I won't use more than 1500w. It's for future upgrade.

                I haven't uploaded directly here because of the high resolution.

                I'll post them soon.

                Comment


                • #9
                  Originally posted by Takis View Post
                  For now I won't use more than 1500w. It's for future upgrade.

                  I haven't uploaded directly here because of the high resolution.

                  I'll post them soon.
                  I am pretty new at this, but there seems to be a huge difference in the amount a 3000 watt inverter and a 1500 watt inverter draws just by being plugged in. I remember something around a 50 watt an hour difference, or about 1200 watt hours a day.

                  Comment


                  • #10
                    My previous one 1200w was pulling 30w per hour

                    Comment


                    • #11
                      IMG_20200628_211630.jpg

                      Comment


                      • #12
                        IMG_20200628_212746.jpg

                        Comment


                        • #13
                          Originally posted by chrisski View Post
                          When I see 24 VDC, 300ah battery, and a 3000 watt inverter, I start thinking that that system is way underpowered and a fire hazard.
                          You scared me. While I'm using half of the power, any serious points to pay attention at?

                          Comment


                          • #14
                            the factory example you show in post 11, should be the way you wire, unless a local, licensed electrician tells you otherwise.

                            Sadly, the factory example does not show any circuit protection devices and you should have local guidance regarding wire size and proper fuses or circuit breakers.
                            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


                            • #15
                              Originally posted by Takis View Post

                              You scared me. While I'm using half of the power, any serious points to pay attention at?
                              I’m new to this also, but these are some of the things I noticed when designing my system, and I’ve purchased the panels, wiring, battery monitor, and some other hardware, and will purchase the batteries And charger in the next few weeks, then get the inverter. I’m going with lead acid batteries and will limit myself to a 1000 watt inverterPer 400 AH of battery bank and 12 VDC. That isn’t written anywhere, but is a rather conservative number based off the stickies and other websites.

                              As I’m reading reviews on Amazon, I see a lot of the lower reviews on inverters from people not using them correctly. An example is a 2000 watt inverter with 6 gauge wire, where the guy complains the inverter is not strong enough and he can smell insulation burning. When I do the wire size calculators, even for a battery to inverter run of only a couple feet, I come up with a much thicker gauge wire needed. Something like that I consider dangerous.

                              On another video with a guy with a 1500 watt inverter on a 400 ah system with lead acid batteries. His voltage dips a full volt down into the 11 VDC range when he puts a load on the inverter. To me, that is drawing energy from the battery quicker than it can provide it, which I think A more proper term would be more than the C/4 rate. I think that pushes batteries harder than they are designed and puts off a bit of heat and can shorten the life of a battery. In the same video he shows how swapping to an equivalent sized lithium bank, the voltage drop is much improved.

                              When I was looking at starting, I wanted to purchase on off the shelf kit and install that and save money, but I found most were missing a lot of stuff. I found that I am spending 4 times what the panels cost for my system, a lot of the extra cost is the batteries. When I started to learn about what was needed, I saw a lot of these systems had 1200 watt panels with a single battery shown, which is misleading. I would use 8 batteries on that 1200 watt system and wire it to 24 VDC. Missing 7 batteries adds up on cost. There was other stuff missing like combiners with circuit breaker protection. Also, none had battery monitors. All the systems that had inverters did not have panels, batteries, wiring, and inverters in a combination to make me feel safe based off what I saw in the stickies.

                              I think people build systems for their RVs that have things like a 3000 watt inverter powered by a 400 watt panel, 12 VDC, and a 200 watt battery bank and don’t have trouble with it, mostly because they don’t use it for an extended period of time, like for only a day or two, or end up going to a campground and use shore power and not their solar power system. I think the fire risk would get worst the longer the system is used, like an off grid system that is used 24/7/365. I feel if I put a 3000 watt inverter in, I could avoid pushing it to the limit, but the minute I left the RV, I’m not sure my wife, my son, my daughter, or their friends would not try plugging too many power hungry devices in pushing the limits.

                              A guy in a local craigslist ad says he can install solar in an RV from $400. I want to take him up on his offer since its costing me about ten times that much. I’m sure its just a bait and switch with his $400 system being basically a good 12 volt charger for a car battery, and I’msure it would be much more than I’m paying to install myself for a same sized system.

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