Wiring Solar Panels: Series or Parallel?

Discussion in 'Solar Panels' started by WindyFAQ, Sep 4, 2012.

  1. WindyFAQ

    WindyFAQ WindyNation FAQ Staff Member

    See attached diagram

    Attached Files:

  2. leamywind1

    leamywind1 WindyNation Engineer

    Series connection to raise the voltage -------amps stay the same.

    12v 3 amps 12v 3 amps 12v 3 amps 12v 3 amps
    solar arraylar.jpg

    Each panel is 12v at 3 amps. 12v x 4 panels is 48 volts at 3 amps=144watts (36w x 4 panels)=144w

    12v @ 3 amps=36w/panel or a total of 144w when all tied in a series connection
  3. leamywind1

    leamywind1 WindyNation Engineer

    Parallel connection to raise the amps....voltage stays the same.

    solarr arraya.jpg
    12v @ 3 amps per panel

    Voltage stays the same throughput the wiring. Just add up the amps .....3+3+3=9 amps @ 12 volts=144 watts

    Low voltage or High voltage string connections
    Using higher amps requires larger wire sizes and voltage drop problems. It is more efficiant to run a higher voltage configuration on any system to get the same amount of watts regarding solar. Their are new charge controllers that can take a high voltage solar panel input and then convert them back to a battery voltage like 24v or 48v.
    So you could run lets say 1(0) 12v panels at 3 amps each in series. That's 300watts of solar at 120 DC volts and at only 3 amps. So the wire size is smaller buy depending on your wire run.

    Do the same with parallel 12v DC at 9 amps. 10 panels at 12 Dc volts @3 amps each. Now adding up the amps only it would be 12 DC volts at 30 amps. Now you need a big wire plus not including the voltage drop calculation which together could put the wiring up to a #6 or larger vs using a series connection and only using maybe a 15a or 20 amp wire.

    So in nut shell a series connection is good for med. to large systems
    and a parallel connection is really only good for smaller systems which also requires more wiring.

    A larger solar array is usually in a series parallel connection having 1 per string per DC breaker in the combiner box. Each DC breaker is in parallel with each other making up the overall amps.
    Having one string of panels at 12v dc at 3 amps per breaker. Lets say you have 3 strings and 3 breakers 1 breaker per string in the combiner box. Now you add up all the amps that go through each breaker which would be a total of 9 amps. 12v x 9 amps =180 watts.
    If you had 3 solar strings of 48v at 3 amps per sting it would be 9 amps total in the combiner box. 48v x 9a =432w.
    Grid tie is another animal but way easier. DC requires lots of calculations, wire and fuses

    combiner box.jpg

    My 2 cents
    TomT likes this.
  4. One question.. Do I have to conect the PV at same voltage as the battery Bank?.
    My inverter is 24v do I have to connect both at the same Volt In the charger controller
  5. Tuicemen

    Tuicemen Solar Guru

    Carlos Sanchez likes this.
  6. One more...
    Can I combine two diferent Solar Panels in one charge controller?
    I have 2- 265w 9amp and 6-100watt 5amp each.
    It is possible? Total of 48amp.
    The charger is 80amp and that combination is 48 amps.
    Last edited: Jan 6, 2018

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