Solar pannel mounting on a curved roof?

Discussion in 'Solar Power' started by Hippyjake, May 19, 2009.

  1. Hippyjake

    Hippyjake Deleted User

    Greetings all

    I have 6 large solar panels monted on my shed roof that i use to power things in my bedroom at the moment, but i have just got a van and was thinking of ways to fix them to it. Its an LDV pilot and the roof is not flat so im not really sure how to fix them on.
    Im thinking i might have to get a roof rack and modify it to mount the 6 panels. This i fear will make it easy for nasty people to steal.
    Also as a roofrack will raised up from the roof i fear the wind may be too much for the pannels to take, and may rip off driving down the motorway.
    maplin no longer sell the panels on their own, but are selling them in sets of four.
    60W Solar Power Kit > Maplin
    I dont have the mounting frame these come with and at the moment my six panels are screwed to a wooden frame i made and attached to my shed roof.
    Would it be ok to mount them on a roof rack and how can i make the roof rack hard to take off? Or is there another solution i have not thought about?

    any tip or tricks will be greatfully recived :BigGrin:

    Thanks all
     
  2. hilldweller

    hilldweller Funster Life Member

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    You are quite right to worry - those are damned big panels and I seem to recall not fully waterproof ( in the sales blurb ).

    Even flat you can be in trouble, remember 2/3rd of a plane's lift comes from the top of the wing, so even if you don't get wind under it you need to think in terms of a deflector to protect the top.

    Good luck, it's not a trivial exercise.
     
  3. Geo

    Geo Trader - Funster

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    There you go, Ive worked it out for you, you should be good for 140mph before you take off:Wink: where the Reynold's number, . The expression for the drag force given by equation (6) is called Sods law
    When the value of Cd is substituted in the equation (5), we obtain the expression for terminal velocity of a motorhome with large solar roof panels under creeping flow conditions::Rofl1::Rofl1::Rofl1:
    Geo
     
  4. pappajohn

    pappajohn Funster Life Member

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    correct on both counts brian...:thumb:
    they are big for 60w panels and they aint waterproof:Sad:

    but mine, not one of the above, is mounted 3" above the roof and i have no trouble with it at all at motorway speeds or with the pressure wave from the front of HGVs/coach's coming towards me.

    of course you know an aeroplane with a flat wing is only a tube with a plank on it.
    it only becomes a wing when the top is curved causing the air travelling over it to travel much faster (curve = larger leading edge to trailing edge area) than the air going under it causing a partial vacuum on top so producing lift.:thumb:

    solar panels are flat....:Doh:
     
  5. Frankia

    Frankia Read Only Funster

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    Using solar panels to power things in the bedroom?:Rofl1:
     
  6. The Wild Ones

    The Wild Ones Read Only Funster

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    I was wondering how I could increase my mpg!! :Rofl1:.

    Seriously though, apart from the size of those panels is the weight? when I looked to buy some, the weight on the box was 28.4 kg, I wouldnt put that kinda weight on my roof not permanently anyhow. Great buy though currently £199 for 60w.
     
  7. Hippyjake

    Hippyjake Deleted User

    I cant help but feel that most of you are taking the p155. so I am not going to post another question here in the future as this was the first question i have posted and got mostly laughed at :Tongue1: Thanks to those who didnt laugh but to those who did shame on you formaking the forums one person lighter from now on.

    For future reference, these panels state in the instructions (atleast the ones i brought individually) that they are waterproof and can withstand hail upto 25mm and mine have been out in the garden for 3 years in all weather and still work great. I even throw buckets of water over them in dry weather to wash them as they get covered in pollen and bird poop. They do weigh a fair amount but its not like the weight will be all in the same place like a stiletto heal, and the shed they are on at the moment is made form PVC with one metal beam supporting the roof down the middle. so im sure the van can take the weight if a PVC shed can. My concern was them being stolen or ripped off the roof at 70mph as i Remember whan i was a tiddler going on a camping trip with my mum that the roof rack full of stuff got pulled off going down a dual carageway and luckly there wasnt anybody behind at the time:Eek!: But as you guys seem to be more concerned about airplanes than solar panels i feel i am wasting my time here.
    90Watts worth of solar panels is very usefull energy and i would really like to use them when on a camping trip in the future.........
     
  8. hilldweller

    hilldweller Funster Life Member

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    Of course we are, this is FUN.

    But it's not malicious, no-one is having a go at you personally, just look at all the messages, they are all light hearted.

    I think we are all old enough not to take life too seriously so we jump in our little wheeled boxes and avoid the worst of it.

    Cheer up, you were given some hints and you are right, 90W ( but only under best possible conditions ) is plenty for most people.
     
  9. Wildman

    Wildman Read Only Funster

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    I have three of those panels fitted inside my roof rack, this protects them from the wind, tree branches and suchlike. To secure the roof rack to the van I would use snapoff bolts so no heads remain. mine is on a coachbuilt so screwed and bolted on. The best bet is not to worry about them being stolen. Just make sure they are covered by insurance. Photos and an agreed value should do the trick. Before you start to feel picked upon read some more posts. We all like a laugh but there is some genuine help out there as well, besides most of the **** taking was not aimed at you but the poster of another reply. So calm down and give up another chance. This is a fun site get it FUN:Rofl1::Rofl1::Rofl1::Rofl1:
     
  10. Losos

    Losos Read Only Funster

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    Hippyjake - As Wildman has said I honestly didn't read any of the above as having a go at you.

    Just for the record on the UK Workshop forum I once posted a question about carrying 8x4 sheets of plywood on the roof and all the replies were light hearted and made reference to aeroplanes :RollEyes: I wasn't bothered because I got the answer I wanted :Smile:

    As it happens I was pondering the question of mounting solar panels on a curved roof on my van but I've tacken the easy way out and I will be getting a firm of MH aftermarket installers to do the job :Rofl1:

    If you're still here (I hope you will be) when they do the job I'll come back and tell you how they got around the curved roof thingy.
     
  11. The Wild Ones

    The Wild Ones Read Only Funster

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    I have to agree here too, as was said above it was never meant too be condescending and if you read carefully behind the humour is a serious message. Most MH panels that I have encountered with my limited experience are less than 10 kilo's even for 60 watter's.

    From what I have read panels have to have a gap of about 10mm between panel and roof for cooling. Generally these are either secured using nuts and bolts, or using sikaflex.

    The wind resistance at speeds will increase the stress on the fixings through `lift' as has been mentioned. As a simple rule the higher the weight under these conditions the higher the stress on the fixings.

    Now imagine following a MH if one of these breaks off and hits you!! bad even at 50mph and 10 kg. Even worse at 28.4 kg.

    Now, yes the load is spread evenly on the roof, which is a good thing for it, but the large surface area increases the stress, but as was put earlier may act in the same way as an aircraft `wing'.

    My joke actually had a little truth to it. You see under the above conditions if a vehicle is subjected to lift by any means, rolling friction may be reduced, even ifonly fractionally with the above example.

    Apologies if you have been left to feel this way, however sometimes in life humour can be a good way of dealing with serious situations or concerns, and it would be a shame for you to knee jerk in this way.

    I actually decided to buy a smaller panel in fact this one:-

    43W Solar Panel Kit > Maplin

    Havnt fitted it yet but intend to do so before my wild camping in the summer up north.
     
  12. davetthedon

    davetthedon Read Only Funster

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    Touchy, touchy, touchy. Bad trip last night Hippy? This forum does exactly what it says on the tin....FUN. If you can't take the humour with the excellent advice given by the tireless members then move on mate!! If on the other hand you're just having a bad day, then all is forgiven too.
    ATB
    DaveT
     
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