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  • VV, VA, and PF.

    My rc200 inverter remote displays readings in VV, VA and PF to which I say WTH. It does however also display V, Hz,and A out, which is useful. The manual does not explain what these other terms are, only that it displays them.
    900W, 40A MPPT, 230AH FLA,24V Samlex 1500W

  • #2
    PF = power factor
    VA = volt amperes
    W = watts

    If you divide the W by the PF you will get VA.

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    • #3
      There are 6 numbers displayed: V, A, Hz, VV, VA, and PF. It is the last 3 I am unfamiliar with even the terminology. I guess the "VV" symbol is their way of displaying a "W". Then just to right of the W readout is the VA readout. So it displays both W and VA, and they are not the same.
      900W, 40A MPPT, 230AH FLA,24V Samlex 1500W

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      • #4
        Oh! Sorry, just processed your reply
        900W, 40A MPPT, 230AH FLA,24V Samlex 1500W

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        • #5
          Originally posted by Gdwats View Post
          There are 6 numbers displayed: V, A, Hz, VV, VA, and PF. It is the last 3 I am unfamiliar with even the terminology. I guess the "VV" symbol is their way of displaying a "W". Then just to right of the W readout is the VA readout. So it displays both W and VA, and they are not the same.
          See the last sentence of SunEagle's 1732 hrs. post this date.

          They are only the same if the Power Factor == 1.0. High school physics, at least it used to be.

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          • #6
            I see. And, yes I already apologized for that. I'm just wondering what to use the PF for. If i am running a 1000W item and have a PF of 0.5, does that mean it is costing 2000W DC from the battery to produce my 1000W AC?
            900W, 40A MPPT, 230AH FLA,24V Samlex 1500W

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            • #7
              Originally posted by Gdwats View Post
              I see. And, yes I already apologized for that. I'm just wondering what to use the PF for. If i am running a 1000W item and have a PF of 0.5, does that mean it is costing 2000W DC from the battery to produce my 1000W AC?
              Bad power factor means a lot of power is flowing back the wrong way 120 times a second. Your inverter will
              have to be designed to deal with it, the efficiency hit will depend on how its designed. Bruce Roe

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              • #8
                Thanks bruce. Mine was a PF of around 0.6. Probably because I was only drawing 28W from a 1500W 24V inv. The PF should be closer to unity as I increase the power draw perhaps. Still waiting on some parts until I hook up the bigger batteries.
                900W, 40A MPPT, 230AH FLA,24V Samlex 1500W

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                • #9
                  Originally posted by Gdwats View Post
                  Thanks bruce. Mine was a PF of around 0.6. Probably because I was only drawing 28W from a 1500W 24V inv. The PF should be closer to unity as I increase the power draw perhaps. Still waiting on some parts until I hook up the bigger batteries.
                  Most small motors, like fans or pumps are not efficient so they create a low PF. Incandescent light bulbs and heaters will generate a higher PF close to 1.0.

                  A low PF doesn't mean you are using more Watts. It means you are drawing more Amps due to the inefficiency of the load. Just adding load does not guarantee a high PF.

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                  • #10
                    I see. Thanks again. And here I was thinking the PF was more a function of the inverter, now I know it is mostly a function of the devices to which the load is being applied. I learn so much here. I am feeling "safer" too, with the right fuses in the right place and a grounding rod set up and wired correctly.
                    I've switched from 12 to 24V, hooked up 2 strings of 3S arrays etc..None of which I had the confidence or knowledge to do myself, until I found this forum.
                    Believe it or not I was chemist of the year at PSU and minored in physics. Electronics is my weak spot. Never took any classes in electronics, other than simple circuit class. I know A,V, I and r quite well, but usually dealt in ergs, joules,luminosity and other units of extremely large and small energies. I know nothing of electronic wiring but Im getting the concepts. I can solve shrodingers wave equations, but cant figure out the best place to put a fuse on my own.
                    So I am not an idiot, or a genius, just a guy trying to learn solar best practices and nomenclature. So again, I thank you all, and slap a couple.
                    900W, 40A MPPT, 230AH FLA,24V Samlex 1500W

                    Comment


                    • #11
                      Originally posted by Gdwats View Post
                      I see. Thanks again. And here I was thinking the PF was more a function of the inverter, now I know it is mostly a function of the devices to which the load is being applied. I learn so much here. I am feeling "safer" too, with the right fuses in the right place and a grounding rod set up and wired correctly.
                      I've switched from 12 to 24V, hooked up 2 strings of 3S arrays etc..None of which I had the confidence or knowledge to do myself, until I found this forum.
                      Believe it or not I was chemist of the year at PSU and minored in physics. Electronics is my weak spot. Never took any classes in electronics, other than simple circuit class. I know A,V, I and r quite well, but usually dealt in ergs, joules,luminosity and other units of extremely large and small energies. I know nothing of electronic wiring but Im getting the concepts. I can solve shrodingers wave equations, but cant figure out the best place to put a fuse on my own.
                      So I am not an idiot, or a genius, just a guy trying to learn solar best practices and nomenclature. So again, I thank you all, and slap a couple.
                      Neither idiot or genius, but just someone with the cart before he horse 1X/ in a while and in the middle of the brain distribution like the rest of us.

                      Comment


                      • #12
                        You got the first step right - asking questions. So many people bull their way through till something burns up !

                        Fuses go closest to the power source. They even make special fuses that bolt onto the battery terminal - MRBF

                        For an interesting read about Power Factor (loads cause lousy power factor, but the generator and inverter have to be able to handle the overloads poor PF causes) read this long article written about Stage and Movie lighting with portable generators. Several illustrations given in it.
                        http://www.screenlightandgrip.com/ht...rator%20basics
                        Last edited by Mike90250; 09-10-2017, 01:06 AM.
                        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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                        • #13
                          Great, I will. I did end up getting a dual mrbf from blue sea, and installed a 40A for mppt and 125A for the inverter installed on the pos terminal. Very handy item!
                          900W, 40A MPPT, 230AH FLA,24V Samlex 1500W

                          Comment


                          • #14
                            Originally posted by SunEagle View Post

                            Most small motors, like fans or pumps are not efficient so they create a low PF. Incandescent light bulbs and heaters will generate a higher PF close to 1.0.

                            A low PF doesn't mean you are using more Watts. It means you are drawing more Amps due to the inefficiency of the load. Just adding load does not guarantee a high PF.
                            Actually efficiency is a different concept entirely, and relates input power (watts, not VA) to output mechanical or other power (watts, BTU, Horsepower).

                            A low PF does correspond to some part of the inefficiency because of energy wasted in resistive heating in the windings.
                            SunnyBoy 3000 US, 18 BP Solar 175B panels.

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                            • #15
                              Originally posted by inetdog View Post

                              Actually efficiency is a different concept entirely, and relates input power (watts, not VA) to output mechanical or other power (watts, BTU, Horsepower).

                              A low PF does correspond to some part of the inefficiency because of energy wasted in resistive heating in the windings.
                              You are correct. I guess I was referring to the efficient use of the transformer, generator or inverter.

                              If the power factor is low then you end up wasting it's amp availability by loading up the transformer even though your "load wattage" doesn't change.

                              In past lives I have installed many PF correcting capacitor banks to reduce the transformer loading. It was much cheaper then putting in a bigger transformer and switch-gear.

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