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Thread: Solar panels - parallel or series?

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    Solar panels - parallel or series?

    Looks like st some stage soon I'll be getting 5 x 95 watt solar panels which I was then thinking of running into an MPPT charger such as a Victron 100/50 or similar.

    Being an Electrician I'm thinking I should wire them in series as the controller can handle 100 volts (I'm assuming here the open circuit voltage will be around or just under 100 volts with the panels connected in series here but haven't got the panels yet to check this).

    So, for the solar gurus, is this the correct way to go? Thinking that doing this will reduce voltage drop and allowing charging to continue down to a lower light level as a higher voltage will be maintained on the input for longer.

    Thoughts/theories?
    If you need to contact me please email homestarrunnerau@gmail.com - thanks - Gav.

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    I’m no guru but sound good to me....

    What brand/type of panels??

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    Quote Originally Posted by weeds View Post
    I’m no guru but sound good to me....

    What brand/type of panels??
    No idea yet - they are a few years old and I probably won't have them for a couple of weeks. I'm not expecting them to perform like new but they should be good for a while yet by the sounds of it.
    If you need to contact me please email homestarrunnerau@gmail.com - thanks - Gav.

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    Quote Originally Posted by Homestar View Post
    Thinking that doing this will reduce voltage drop and allowing charging to continue down to a lower light level as a higher voltage will be maintained on the input for longer.
    im not sure if this will reduce voltage drop.
    but im thinking it will decrase resistance though your wires.
    less amps = less resistance which is useful on hot days.

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    Solar panels - parallel or series?

    Hadn't thought about lower conductor temp that may be possible in a positive temperature coefficient conductor by lowering the amps.
    If you need to contact me please email homestarrunnerau@gmail.com - thanks - Gav.

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    My suggestion is to go series-parallel, keep the panel voltages to under 60V where contact isn't a safety hazard. For 36 cell units OC voltage will be slightly higher than 20V especially in cold weather. Five panels is of course an awkward number to do that with.

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    Quote Originally Posted by Homestar View Post
    Looks like st some stage soon I'll be getting 5 x 95 watt solar panels which I was then thinking of running into an MPPT charger such as a Victron 100/50 or similar.
    One of the reputably better regulators around.

    Being an Electrician I'm thinking I should wire them in series as the controller can handle 100 volts (I'm assuming here the open circuit voltage will be around or just under 100 volts with the panels connected in series here but haven't got the panels yet to check this).
    Panels of around 100W tend to have an open circuit voltage (Voc)of between about 18V and about 25V so you may, or may not, be on safe ground. The only way to be dead set certain is to measure Voc.


    So, for the solar gurus, is this the correct way to go? Thinking that doing this will reduce voltage drop and allowing charging to continue down to a lower light level as a higher voltage will be maintained on the input for longer.

    Thoughts/theories?
    Series connection will certainly reduce I2R losses over parallel connection given the same wire size.
    Cheers,
    Mark F...
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    Hi,
    If I have understood what I have been told, there is also the fact that shade on one panel will lower the output of a series array more than a parallel array.
    Not that you have much choice with five panels.
    Cheers

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    I have always thought that parallel was better when panels could be in partial shade. If wired in series, the one in the shade pulls the others down & the output is less than if they were in parallel.
    + 2016 D4 TDV6

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    Ah, hadn't thought about the shade on one panel affecting the whole system. I could easily go with 4 panels and do a series parallel setup.
    If you need to contact me please email homestarrunnerau@gmail.com - thanks - Gav.

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