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  • Wattage

    Does wattage behave the same as voltage and current when panels are wired in series or parallel?

  • #2
    Power aka Wattage is a product of voltage and current, Therefore Power always Adds regardless if in series or parallel.
    Last edited by Sunking; 10-02-2016, 11:43 AM.
    MSEE, PE

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    • #3
      Thanks Sunking, I thought it always added but wanted to check with a MASTER.

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      • #4
        You are welcome. Look at this way for example let's say you have a quantity of 4 12-Volt 100 AH batteries. Each battery has a capacity of 12 volts x 100 AH = 1200 watt Hours. Add them all up and you have 4 units x 1200 wh = 4800 wh or 4.8 Kwh

        Makes no difference how they are arranged:

        All in Parallel and you have 12 volts @ 400 AH = 4800 wh
        2 x 2 and you have 24 volts @ 200 AH = 4800 wh
        All in series you have 48 volts @ 100 AH = 4800 wh

        OK that is theory, not practice. So do not leave thinking all 3 circuits are equal because they are not. 48 volts is the superior circuit because it is more efficient and 9 times out of 10 cost less.
        MSEE, PE

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        • #5
          Originally posted by Sunking View Post
          ........OK that is theory, not practice. So do not leave thinking all 3 circuits are equal because they are not. 48 volts is the superior circuit because it is more efficient and 9 times out of 10 cost less.
          Reasons:
          Smaller gauge wire: 50A vs 200A
          Fewer 60A Charge Controllers. 14V @ 60A = 840W PV max, or 56V @ 60A = 3360W PV max (14V is a nominal charging voltage for a 12V battery, 56V for a 48V bank)
          Less expensive DC Circuit Breakers, 50A vs 200A
          Less resistive loss in the wires and battery plates/connections
          https://en.wikipedia.org/wiki/Electr...nd_conductance

          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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          • #6
            How many watts do you folks actually get from your panels? Was watchin a you tube where the guy had 2 100 watt panels and was only getting a little over 100 watts with them.

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            • #7
              On a cloudy day, I get LESS than 10% of nameplate. So my 5Kw of PV is making about 400w of power..... So I have a large battery bank, to get through 1 day, and day 2 I start running the generator, day 3 . don't ask about day 3, when it's sleet, can't walk and I forgot to run the generator on day 2.
              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


              • #8
                Originally posted by kellyvb View Post
                How many watts do you folks actually get from your panels? Was watchin a you tube where the guy had 2 100 watt panels and was only getting a little over 100 watts with them.
                Sounds about right if he used a inexpensive PWM controller. FWIW quit watching Screw Tube,about all of it is worthless from people who have no clue. We got one guy that shows up here abd we beat up in him pretty good. He makes videeos on solar power and has no clue what he is doing or talking about.
                Last edited by Sunking; 10-03-2016, 11:21 AM.
                MSEE, PE

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                • #9
                  On a "average" clear day, I can get 80% of of nameplate power. Yesterday, here is a screenshot of my 2Kw array just as clouds cleared, and the panels were still cool, and the batteries low. 2,217 watts from a 2,000w array. Normally I'm getting 1,600 or so, as batteries start off slow with the AM sun, and as they charge up, the rate decreases
                  (pay no attention to the 16V meter needle - that's an artifact to properly set my BTS sensor for NiFe bank on a Pb based controller)

                  MidnightClassic Full Power.jpg
                  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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