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  • Help on mono 5x5 6x6

    Hi

    I am planning to make a 3KW system and need to determine which kind of cells I should use and where to buy them.

    specs for 5x5 from Everbright solar:
    Specifications:
    Open circuit voltage Voc: 0.604-0.623 V
    Close circuit current Isc: 4.881-5.300 A
    Maximum power voltage Vmax: 0.473-0.528 V
    Maximum power current Imax: 4.429-4.924 A
    Power: 2.1-2.6 watts
    Efficiency: 14%-17.5%
    Dimension: 125 mm X 125 mm, or 5X5 In.
    Thickness: 0.2mm, or 200 um

    And specs for 6x6:
    Cell Specifications: Rated power : ~4 Wp
    Open circuit voltage: 0.610v -0.621v
    Short circuit current: 8.18 amp - 8.78 amp
    Operating voltage: 0.488 v - 0.50 v
    Operating current: 7.51 amp - 8.14 amp
    Weight: Just above 6 grams, or 0.2 oz.

    Am I wrong to think that if I make two panels with the same amount of solar cells the 6x6 panel would give almost twice(1.7) as much as 5x5 panel?

    Is it really necessary to make 18v panels? I am going to charge 6x2v 1200A batteries with it. Isn't it so that Chargers and Inverters that accept from 10v are not uncommon?

    Are there other places that sell cells except Everbright?
    If I want to buy a thousand cells is it possible to buy from the manufacturer?


    Thanks
    Metacom

  • #2
    Welcome

    Just a couple of things. Unless you have had experience with building panels before, and understand all the ways they can fail and leak, there is a lot more than a wood frame and some window glass. Any moisture (including unseen water VAPOR) will quickly degrade your cells, and your panels will cease working.

    3KW is a LOT to be building for your first try. (How do I know this is your first try ? The questions you ask)

    As to 18 V for battery charging.
    Lead acid batteries, need about 15V to charge, and after you run your panel output thru a Charge Controller, a volt or two is lost in the controller. Additionally, in hot weather, a hot panel will have lower voltage, and you may be unable to complete a full charge.

    12V system choice
    When you plan out a system, the guideline is 12V for each KW. if you want a 2KW system, you want to step up to a 24V battery, and a 3KW, up to 36V or 48V. What happens as you increase AMPS, you need to increase the wire size to larger and larger, to keep resistive losses below 3%.

    Another problem is many parallel batteries. It becomes difficult to have parallel batteries equally share the load. Series batteries inherently have no problems, you get the same wattage, less losses, less problems.

    Good Luck
    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
      Metacom,

      Here is my answer.

      Am I wrong to think that if I make two panels with the same amount of solar cells the 6x6 panel would give almost twice(1.7) as much as 5x5 panel?

      [COLOR="Blue"]Sure with the 6x6 cells, you will get more output from the panel. Because the panel is bigger than 5x5.

      12V sys: 5x5 cellsx36pcs=0.5625mxm
      6x6 cellsx36pcs=0.8761mxm [/COLOR]
      Is it really necessary to make 18v panels? I am going to charge 6x2v 1200A batteries with it. Isn't it so that Chargers and Inverters that accept from 10v are not uncommon?

      [COLOR="blue"]Yes, you need 18V module which made by 36 cells.[/COLOR]

      Are there other places that sell cells except Everbright?
      If I want to buy a thousand cells is it possible to buy from the manufacturer?

      [COLOR="blue"]It is not easy you do your own the 3KW, I could help you to buy the cells if you really want to do yourself[/COLOR].


      Thanks
      Metacom

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