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Thread: Solar panels in series or parallel?

  1. #1
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    Question Solar panels in series or parallel?

    Hi,

    Recently i obtained two 180 Watt solar panels. They will be mounted on the roof of truck. What's are the pro's / con's of series or parallel solar panel connections.

    Only from a reliability / redundancy point of view the best option seems parallel. In the past years i had a few near misses - almost loosing one panel while driving in the mountains while stones came rushing down. These panels were connected in series.

    Anyone?
    Cheers
    LaptopNomad
    ------------------------------------------------------------
    Extreme laptop travel in Asia, Middle-East and Africa
    www.laptop-junction.com

  2. #2
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    Assuming you have a shunt or PWM controller on a 12 volt system you only have 1 choice; parallel.
    MSEE, PE

  3. #3
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    It's a 24 volt system based on two 230Ah AGM batteries. Solar panels will be connected to MPPT controller, probably an IVT again but looking around if there's anything better on the block.

    So Series or parallel setup? The solar panels are identical from the same source. Also need to think about the bypass diodes - since the panels have none at the moment.
    Cheers
    LaptopNomad
    ------------------------------------------------------------
    Extreme laptop travel in Asia, Middle-East and Africa
    www.laptop-junction.com

  4. #4
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    I never knew that solar panels could be connected in series or parallel.

    I am now educated =).
    good read.
    But what if you use 12% and only get 8% energy return not filling a battery completely off the solar array- is this considered a cycle? Mmmmmmm mauh brain's sizzling
    [/QUOTE]
    If a pigeon had his brains it would fly sideways

  5. #5
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    Quote Originally Posted by LaptopNomad View Post
    It's a 24 volt system based on two 230Ah AGM batteries. Solar panels will be connected to MPPT controller, probably an IVT again but looking around if there's anything better on the block.

    So Series or parallel setup?
    Series is the right way to go with a MPPT charge controller. Besides it is about the only option you have assuming your panels are made for 12 volt system you have to wire them in series.

    Quote Originally Posted by LaptopNomad View Post
    The solar panels are identical from the same source. Also need to think about the bypass diodes - since the panels have none at the moment.
    Bypass diodes I hope not, the panels should have them built in already.
    MSEE, PE

  6. #6
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    Quote Originally Posted by Sunking View Post

    Bypass diodes I hope not, the panels should have them built in already.
    There are no diodes in the junction box, while the current BP solar panels have those
    installed by default

    See here for an impression of the panels; Panel spec suggests 12 Amp bypass diodes.

    Solar panels from China.
    Cheers
    LaptopNomad
    ------------------------------------------------------------
    Extreme laptop travel in Asia, Middle-East and Africa
    www.laptop-junction.com

  7. #7
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    Quote Originally Posted by LaptopNomad View Post
    There are no diodes in the junction box, while the current BP solar panels have those
    installed by default

    See here for an impression of the panels; Panel spec suggests 12 Amp bypass diodes.

    Solar panels from China.
    One more reason not to buy communist products :becky:
    MSEE, PE

  8. #8
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    Quote Originally Posted by Sunking View Post
    One more reason not to buy communist products :becky:
    pretty much but for the price, is it worth the risk?
    Now who wants to play Russian roulette with a slide action hand gun?
    But what if you use 12% and only get 8% energy return not filling a battery completely off the solar array- is this considered a cycle? Mmmmmmm mauh brain's sizzling
    [/QUOTE]
    If a pigeon had his brains it would fly sideways

  9. #9
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    Quote Originally Posted by SpaceOddacy View Post
    pretty much but for the price, is it worth the risk?
    You have to answer that for yourself.

    What I advise clients is stick with names you know and trust that have been around for decades, and will be around for many more. Choose manufactures where solar panels are a very small fraction of their market,like BP, Kyocera, Sharp, and Sanyo. These companies will be around tomorrow to honor warranty replacements and future expansions.
    MSEE, PE

  10. #10
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    Lightbulb

    Quote Originally Posted by Sunking View Post
    One more reason not to buy communist products :becky:


    Had an peculiar experience with communist solar panels in Nepal - were most electronics are hauled over the Nepali Himalayas to the bottomless cheap electronics pit - the Indian and Pakistani market.

    A couple from Swiss decided to change their $$$$$$ expensive Swiss solar panels on their RV in Pokhara, Nepal with cheaper and more powerfull ones with communist origins for a bargain price. (relatively speaking)

    Although the communist solar panels were flimsy compared to the robust Swiss ones, the output was much higher. With the same PWM charger / battery, they got amp ratings higher than ever before. As a bystander i could only think - the swiss panels were probably badly matched with the PWM / battery or had thicker glass to sustain heaps of snow?

    Anyhow - solar electricity is growing rapidly in these regions - with china as the main player - not as a green alternative but because the grid is so unreliable.
    Cheers
    LaptopNomad
    ------------------------------------------------------------
    Extreme laptop travel in Asia, Middle-East and Africa
    www.laptop-junction.com

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