solar panels tied in together

conntaxman
conntaxman Solar Expert Posts: 125 ✭✭✭✭✭
in Solar Beginners Corner #1
what is the best way to tie in together 8 solar panels that put out each 65 watts .Should you connect all the + together and mins together.
this will be with a 12 volt dc sym.
tks
John
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: solar panels tied in together

    Insufficient details.
    There's a few things that make a difference, such as what the Voltage of the panels is (Vmp & Voc).
    Also, whether your using a PWM type charge controller or an MPPT type (which can take higher Voltage input and "downconvert" to the system Voltage).

    If you parallel eight panels you should put a fuse on each panel to prevent damage in the event of a short circuit in one of the panels.
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  • mr.radon
    mr.radon Solar Expert Posts: 158 ✭✭✭✭✭
    #3
    Re: solar panels tied in together

    What you need to look at is the spec sheet for the module. See this example:http://www.kyocerasolar.com/pdf/specsheets/KC65T.pdf
    Most people tie the modules together in series, (+ #1) to (-#2) (+#2) to (-#3)...
    NEC codes don't let you wire more then 600VDC. You want to get the voltage up to reduce the I^2R losses getting the power to the inverter/charge controller.

    There are schematics on-line that can show you have to wire them. Panels typically come with leads and connectors so the process is pretty easy to connect them together in series. Parallel connection is a little more tricky.
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #4
    Re: solar panels tied in together

    You are wanting to run the entire string @ 12 vdc. Therefore you have to wire them all in parallel, that is Plus to Plus to PLus etc, Minus to Minus to Minus etc. As 'Coot says, make sure you install fuses in the parallel array.

    We know this to be a 12 vdc system because of conversations on other threads, AND he revels that in post #1!

    Tony
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #5
    Re: solar panels tied in together
    icarus wrote: »

    We know this to be a 12 vdc system because of conversations on other threads, AND he revels that in post #1!

    Tony

    Of curse if he's using an MPPT charge controller then system Voltage and array Voltage are not necessarily the same.
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #6
    Re: solar panels tied in together

    On another thread he was talking about te Bluesky 2512 controller, which only allows a 12 vdc in put. H was also talking about a Rouge 3024 which would allow 24 vdc input.

    Sorry for any confusion, assuming facts not in evidence,

    T
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  • XRinger
    XRinger Solar Expert Posts: 529 ✭✭✭
    #7
    Re: solar panels tied in together
    icarus wrote: »
    You are wanting to run the entire string @ 12 vdc. Therefore you have to wire them all in parallel, that is Plus to Plus to PLus etc, Minus to Minus to Minus etc. As 'Coot says, make sure you install fuses in the parallel array.

    We know this to be a 12 vdc system because of conversations on other threads, AND he revels that in post #1!

    Tony


    Tony, in parallel arrays, what happens to total output power when one panel is partly shaded?

    Thanks,
    Rich
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #8
    Re: solar panels tied in together

    In parallel arrays, when one panel goes into shade, the only loss is from that one panel, (or portion of that panel depending on how it is built) A shaded panel in series array can have a much more significant effect on the entire array.

    I some times test each panel by covering each one with a blanket in turn and recording the output drop, when the output didn't drop I know I had a problem. My panels are wired in parallel.

    Tony
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  • XRinger
    XRinger Solar Expert Posts: 529 ✭✭✭
    #9
    Re: solar panels tied in together

    I was thinking that might be the case, but wasn't sure.

    Since my ground mounted panels are located in a poor location, sometimes
    one or two are in the shade while the other two are getting good sun..

    They are in series, so I can use makeshift (AKA Free) cabling. If I did go parallel,
    I would have to invest in some real copper..
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #10
    Re: solar panels tied in together

    there will be a loss in either configuration. the series arrangement if it has bypass diodes will not only drop the pv in question or portion of the pv, but will introduce a vdrop from each diode the power passes through.

    in a parallel arrangement a problem exists because there normally aren't any blocking diodes on each pv because most think only of the battery backfeeding to the pvs at night which most controllers will stop. that shaded pv will dissipate a small portion of the power from the output of the other pvs as the power does not have any controller or diodes to normally stop it. placing blocking diodes on each pv will help, but will also introduce a vdrop from each pv that is undesirable. moral of story=shading bad.
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