200W of solar panels - 2 big or 5 small?

Discussion in 'Solar Power' started by peterc10, Nov 1, 2015.

  1. peterc10

    peterc10 Funster

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    The dealer has agreed to fix 200W of solar on our new Hymer. He is suggesting that he will use 5 small square 40W modules to do this. I have never heard of this type before - on my present van I have 2 x 100W panels.

    Anybody used these smaller modules rather than larger ones please? Are they OK?

    Many thanks
     
  2. hilldweller

    hilldweller Funster Life Member

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    Less joints you have the less possible failures. I wonder if he's got some old stock 40W panels no-one wants.
     
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  3. Techno

    Techno Funster Life Member

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    I'd want a scale drawing of what they propose. It sounds poor to me.
     
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  4. Lenny HB

    Lenny HB Funster

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    Sounds a right bodge, 40 watt panels would work out more expensive plus all the extra brackets and fitting time, I smell a rat. Like @hilldweller says probably old stock trying to get rid of.
    I'd be inclined to tell him to get lost and go to someone who knows what they are doing.
     
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  5. Peter A Forbes

    Peter A Forbes Funster

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    Why? 2 X 100W panels and job done.

    40W are just not on, even 5 of them won't perform as well as 2 100W panels.

    Peter
     
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  6. Gromett

    Gromett Funster

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    Multiple solar panels have a single advantage in that if one is covered by shadow the others still produce providing each panel has blocking diodes.

    Other than that I agree with everyone else. Smells fishy to me unless he gives a decent reason.
     
  7. Abacist

    Abacist Funster

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    I am sure that 4 units are going to take up far more roof space than 2 X 100w panels.

    I would reject the four on the grounds that you want room left for future increased facilities such as satellite TV, internet satellite, air conditioning roof unit and maybe a larger bedroom roof light and so you definitely want to see a plan of the roof leaving room for future possible use.
     
  8. Techno

    Techno Funster Life Member

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    FIVE
     
  9. hilldweller

    hilldweller Funster Life Member

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    And the roof garden and jacuzzi.
     
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  10. Abacist

    Abacist Funster

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    Oh well! even worse then - don't like it myself and wouldn't want to accept that offering myself. Mind you I suppose you are lucky that he mentioned it, he could have just gone ahead and done it!
     
  11. Techno

    Techno Funster Life Member

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    As I said you need a picture, if there are practical reasons for it then it is plausible but very unlikely that 2x100 cannot be fitted.
    The cost of fitting 5 panels compared to two in labour is ridiculous.
     
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  12. Techno

    Techno Funster Life Member

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    This is typical (quality) and provided by @Drexxer This was converted to 300 watts[​IMG]
     
    Last edited: Nov 1, 2015
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  13. errpaul

    errpaul Funster

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    Could be to do with what is already on the roof amd the space available.
    On my roof without removing a roof rack cross bar thing I wouldn't have been able to get anything bigger than maybe 80watt. With it removed I put on a 150w and could fit another if needed.
     
  14. Lenny HB

    Lenny HB Funster

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    He is getting a B678 it is a bit bigger than my Exsis 678 I could get 5 x 100 w panels on my roof.
     
  15. peterc10

    peterc10 Funster

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    Thanks for all the comments so far. Please keep them coming.

    As Lenny says this is on a brand new A class Hymer B678 that I have just bought off the dealer. It would be unfair to name them, but they have a good reputation on here and he has been very good so far, so I am not sure that there are any ulterior motives. I have agreed a deal with him so he is paying for all this whichever way it is done. I just got the impression that he always did it this way.

    There is plenty of room on the roof to fit these so that should not be a problem. And the only thing I may put on the roof in the future is a small fan vent over the kitchen area. If it was so hot that we needed air conditioning, rather than a fan or two then we would move somewhere else, after all that is the beauty of motorhoming.

    I am not sure I understand the comments about taking up a lot more space, given that I always understood that no matter what the size a panel was made of a series of individual cells, and that the amount of power produced per square metre was about the same, only varying with the type and efficiency of the individual cells.

    My only concern were the connections, but then you still have that with 2 panels. I wonder whether one 200W one would be better, but then if it happened to be on the part of the van that was in shade that could be a problem too.
     
  16. Drexxer

    Drexxer Funster

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    209.jpg View attachment 81314
    View attachment 81314 This is the original roof layout from which the dimensions were taken, with the soon to be replaced 90 watt panel
     
  17. Drexxer

    Drexxer Funster

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    And this is the roof with 300 watt's installed

    20150812_102040.jpg





    Andy
     
    Last edited: Nov 1, 2015
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  18. peterc10

    peterc10 Funster

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    OK just found a photo of the top of a B678, and there seems plenty of room at the front to put on whatever I want. So would it be better to have 2 x 100W or one 200W please?
     
  19. StefAndDi

    StefAndDi

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    Peter,
    I asked the same question on here when I was speccing (is that a word) my van.
    The consensus was that two were better than one larger one because of the shade issue already mentioned.
    I went for 2 x 150 watt panels.
    Although I have an Oyster 85 and a roof rack and ladder I still have loads of space left on the roof and my van is only a foot or two longer than yours.
    Stef.
     
    Last edited: Nov 2, 2015
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  20. peterc10

    peterc10 Funster

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    Thanks for everybody's help - yet again this forum has shown it is worth much more than the subs! I have emailed the dealer and asked him to fit 2 x 100W panels instead. There is plenty of room on the front.
     
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