solar panel

Discussion in 'Motorhome Chat' started by gpz, Aug 5, 2013.

  1. gpz

    gpz Funster

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    can any one tell me what is the biggest wattage solar panel you can get for a motorhome and are all panels able to be used for 12 volt may seem a silly question hope someone can help and any rough idea how much a panel costs to buy and fit:BigGrin:
     
  2. pappajohn

    pappajohn Funster Life Member

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    biggest i have seen is around 200watts.

    physical size is a problem on motorhomes as there is already a load of stuff on/in the roof, they are also pretty heavy.

    i have a 170watt panel which is around 6ft by 3ft

    most are 12v but some are 24v

    cost...100watt panel can be bought for around £80 on eBay up to a 200watt at several hundred quid.
     
    Last edited: Aug 5, 2013
  3. cmcardle75

    cmcardle75 Read Only Funster

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    Panels come in lots of sizes, but you don't need a big one. Lots of small ones can fit better onto a congested roof for less money. Most panels are designed for 12V systems, but not all. I went for semiflexible panels, as they are much easier to fit and are much lower profile, so don't affect appearance and fuel economy so much.

    Make sure you get a decent solar charger. I got a 200W semiflexible system for about £300, but fit it myself. Seems to work pretty well. My mains charger is broken (110V 35 year old US system) and the split charge is only working on manual, so I'm using solar only at the moment, but never run out.
     
  4. SomeoneElse

    SomeoneElse Funster

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    The controlling factor is the controller. The older PWM controllers operate at fixed point on the panel's IV curve. This is around 17 to 18 volts so optimised for 36 cell or "12V" panels. The newer MPPT controllers can take a range of input voltages up to 100V or more.

    Domestic panels will have 72 to 96 cells and a optimum voltage of 30 to 40V, these aren't suitable for a PWM controller. Whether these are strong enough to cope with the vibrational loads they would experience on the roof of a motorhome is an entirely different matter.
     
  5. gpz

    gpz Funster

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    solar panels

    thanks for the replys guys,so its the controler that i need to be choosy about ,my problem is my fridge is just 12v so all thought i have a 235 amp i think battery it soon runs it down so thinking solar panel is the way to go anyway thanks again
     
  6. maz

    maz Funster

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    Running a fridge off 12v all the time would need a whole load of solar panels! Presumably you have a compressor fridge then, rather than the more usual type that normally only run on 12v when the engine is running.

    Also 235 Ah is a weird size for a battery ......... :Confused:
     
  7. gpz

    gpz Funster

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    yes thats right Maz compressor fridge seemed a good idea at the time i justwent for the biggest battery i could find at the time i may be wrong about it being 235 amp hr i know its big takes up a lot of room
     
  8. maz

    maz Funster

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    Guess battery could be 235Ah then if it's massive. Must be a pig to lift out when it needs changing! :Smile:
     
  9. steevie

    steevie Funster

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    with a good sized solar panel you should have no power problem with a battery that size, but I dont know how well it would do with your compressor fridge. I have a 250 watt solar panel, house type, which runs at just under 40v, and controlled with a 30 amp 12v[also does 24v] controller.[all from ebay] And two 100 amp hour batteries It is a large panel tho, about 6' by 3', bedded on sikoflex. We have had it now for over two years, and it copes brilliantly, as we never have hook up. Panel was around £200, controller was about £20, and sikoflex £12. You may need smaller ones according to your roof space, but they are easily joined together.
     
  10. Dubiousp

    Dubiousp Read Only Funster

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    I bought a 100w unit of EBAY about 8 weeks ago with a cheap MPPT controller fitted the roof lovely and charges a treat,, I admit weve had sun but even evenings give a trickle
     
  11. gpz

    gpz Funster

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    solar panels

    has anybody fitted any of the flexable solar panels it seems there is a lot of weight saving but do they give the same output as ordinary panels and are there any drawbacks apart from price
     
  12. Techno

    Techno Funster Life Member

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    Yes they get hot due to lack of air circulation. Heat causes reduced performance.
     
  13. cmcardle75

    cmcardle75 Read Only Funster

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    Yes, I have two. Much easier to fit as they don't need brackets, just glue or screw down. Better for fuel economy as they don't jut out into the slipstream. Better for appearance, as you can't see them unless you look down from above.
     
  14. gpz

    gpz Funster

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    solar panels

    can anyone tell me what is the quality difference between chinese solar panels and thoose made in this country chineese ones seem to be cheaper
     
  15. Techno

    Techno Funster Life Member

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    Are there any made in this country? or just badged up by UK sellers at higher prices
     
  16. gpz

    gpz Funster

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    i dont know thats what i wasnt sure about ive seen a few posts saying steer clear of chineese one just wondered if there was any particular reason
     
  17. Techno

    Techno Funster Life Member

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    They are not all the same.
    Visual inspection of the quality of assembly is enough for me to decide. With any panel if it looks shabby it is! I've had 80 watt panels at £75 that are/were superb. The 3x100 watt on my current van are first class at £108 each in January. I've had branded AKT that was at a premium price and poorly assembled.
     
  18. gpz

    gpz Funster

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    so do you have the flexy panels or the rigid ones i was looking at the flexy ones just really for the weight saving
     
  19. Techno

    Techno Funster Life Member

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    This is my current instal
    [​IMG]
     
  20. Techno

    Techno Funster Life Member

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    3 Spanish made panels bought from ebay Germany just fitted last week to a Niesmann
    [​IMG]
     
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