Announcement

Collapse
No announcement yet.

combining two sets of panels.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • combining two sets of panels.

    I want to run this past someone who knows if this will works like I think it should. If I mount two 300 watt panels on the roof in parallel producing 41.2 volts, and then also add two 100 watt portable panels in series producing 47.3 volts into the same 100 volt 50 amp controller. I would have ~88.5 volts going to the controller and between < 16.7 + < 50.6 amps as the output to the battery. (cut off by the controller at max 50 amps if the two flat panels on the roof can get anywhere near that wattage)

    My question is the voltage combined (added together) and the amperage combined to raise the output amperage too? Thanks, Bill

  • #2
    Panels in SERIES need to have the same AMPS rating. The lowest amp panel will limit all the panel amps

    (panels in parallel need to have the same voltage output, the lowest voltage panel will limit all the panels)
    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
      The two panels in parallel will have the same voltage/amperage and the 2 panels in series will have the same amperage/voltage. But when I hook both sets to the same controller they would be different in both voltage and amps. Is that the problem, where the sets connect to the controller?

      Comment


      • #4
        You need the panels with the same wattage (voltage and amperage) in Series.
        Like Mike said.

        What Law of Physics. Balance (Equal) current in Series, Balance (Equal) Voltage in Parallel.
        Last edited by rbclark; 06-02-2018, 01:04 PM.

        Comment


        • #5
          Against the Law of Physics your busted.

          MSEE, PE

          Comment


          • #6
            Originally posted by Bigbillsd View Post
            My question is the voltage combined (added together) and the amperage combined to raise the output amperage too? Thanks, Bill
            Nope. You'd be limited to the Impp of the smallest panels.

            Comment


            • #7
              Does that mean two controllers ( one for each set of panels) wouldn't work either as they would be connected to the same battery bank?

              Comment


              • #8
                Originally posted by Bigbillsd View Post
                I want to run this past someone who knows if this will works like I think it should. If I mount two 300 watt panels on the roof in parallel producing 41.2 volts, and then also add two 100 watt portable panels in series producing 47.3 volts into the same 100 volt 50 amp controller. I would have ~88.5 volts going to the controller and between < 16.7 + < 50.6 amps as the output to the battery. (cut off by the controller at max 50 amps if the two flat panels on the roof can get anywhere near that wattage)

                My question is the voltage combined (added together) and the amperage combined to raise the output amperage too? Thanks, Bill
                I think I understand what you are asking, but your assumptions are all wrong. Do your 300 wat panels comprise of 72 cells and the 100 watt panels consist of 36 cells? If so you can make it work like it stated but your math is all wrong.

                Sounds like your 300 watt panels are 72 cells which will give you roughly Voc = 42 volts. The 100 watt panels Voc = 21 volts. If that is a true statement you can make it work. Wire the two 300 watt panels in Parallel. Wire the two 100 watt panels in series, and then wire them in parallel with the two 300 watt panels. That will get your panel Voc = 42 with a Vmp or roughly 34 to 35 volts enough to use either 12 or 24 volt battery.

                If you operate at 12 volt battery will require a 65 amp controller or 32 amps @ 24 volt battery.


                MSEE, PE

                Comment


                • #9
                  Ah, that is what I am looking for! The panels I am considering are 60 cell LG'sLG300N1K-G4 putting out right around 40 volts VOC and the Grape100w I own in series should put out about 43.8 volts (21.9 each) VOC. The Vmpp volts are 32.5v for the LG's and 36v for the Grapes in Series (18v each). Is that too much of a difference? 32.5 vs 36 or would they just use the lower 32.5 voltage?

                  My thought was to only put out the portable 200watt suitcase panels when needed to bump the available watts to reach the controller's max output of 50 A and only when we are boondocking.

                  Thanks, Bill


                  Comment


                  • #10
                    Originally posted by Bigbillsd View Post
                    Ah, that is what I am looking for! The panels I am considering are 60 cell LG's[SIZE=12px]LG300N1K-G4 putting out right around 40 volts VOC and the Grape100w I own in series should put out about 43.8 volts (21.9 each) VOC. The Vmpp volts are 32.5v for the LG's and 36v for the Grapes in Series (18v each). Is that too much of a difference? 32.5 vs 36 or would they just use the lower 32.5 voltage?
                    If the cell counts are the same, and the cell types are the same, they will generally play well together in parallel.

                    Keep in mind that you'll effectively never see that 32.5V anyway. Under load it will be less, and when it's hotter it will be less. So don't worry about that .5 volts.
                    My thought was to only put out the portable 200watt suitcase panels when needed to bump the available watts to reach the controller's max output of 50 A and only when we are boondocking.
                    If you like. They won't contribute much, but if you have them you might as well use them.

                    Comment


                    • #11
                      Originally posted by Bigbillsd View Post
                      The Vmpp volts are 32.5v for the LG's and 36v for the Grapes in Series (18v each). Is that too much of a difference? 32.5 vs 36 or would they just use the lower 32.5 voltage?
                      Only you can answer that question. What I can tell you is the LG panels will drag the voltage down to 32 volts and eliminate 24 volt battery operation. What that means is you loose 32/36 = 11% of power and voltage.

                      MSEE, PE

                      Comment

                      Working...
                      X