Fitting solar from scratch

Discussion in 'Mech Tech' started by 1973daisey, Jun 22, 2017.

  1. I wonder if its possible to test the individual cells on the panel, they must be designed as a combination of series and parallel cells to get both voltage and current. If just a single cell in a series chain is damaged, then you'll get an open circuit on that complete chain.

    Anyone remember old fashioned Christmas tree lights, one out, all out?

    I'll happily do some "digging", if I get time.

    As mentioned earlier, there's quite a bit to be learned from finding out what happened to both @77 Westy and @scrooge95 's and so it can hopefully be avoided in the future....
    paradox, scrooge95, 77 Westy and 2 others like this.
  2. I’m on Thursday’s overnight ferry to Hull, stopping in the Borders Friday night then on up to Balmedie, near Aberdeen on Saturday. Coming home I’ll be stopping in Troon for one night then somewhere in the midlands and on to the ferry from Newhaven to Dieppe. I really won’t have any time to remove the panels.
  3. Busy busy, well techenders is a while away yet
    Safe travels
  4. You don’t need to go to town on it. If you fancy a weekend away your welcome to crash at mine. Bring your new panel and we can have a mini TE. Happy to help

    What sort of discount they offering +70%?

    These are the panels I have

    Lensun 100W 12V Semi-Flexible Monocrystalline Solar Panel
  5. Ah cheers Ray, that's a very kind offer. I might well take you up on it. Thank you.
    I've probably not got time to do much about it now though, as the bus is off on it's holidays to the seaside on Friday, where it will hopefully return from with nicely reupholstered seats and bed (be gone the brown velour, banished to distant memory forever!).
    I did try to find the Lensun panels, as I know they are the one's yourself and @theBusmonkey have, but they seem a bit scarce at the mo - and also if my ridged roof is going to be an issue, I guess I need to make sure of an aluminium reinforcing layer within them. In fairness the reinforced ones are no different in price, so I guess I should just suck it up and do it before Photonic Universe change their mind on the discount. Sadly it's not 70%!
  6. Those panels I have have the aluminium backed panels and only £100 on eBay.
    scrooge95 likes this.
  7. Mine aren't Lensun but IIRC made in the US by a company called Global Solar. I bought them from a company in California who was dealing in bankrupt stock. At the time thin film panels weren't readily available in this country.
    They are metal backed, in this case very light and thin stainless steel I think, and I then laminated them myself to an aluminium back sheet to improve rigidity.
    They are coated with ETFE which apparently is harder wearing and more light absorbent than cheaper polyester.
    Minefield innit....
    scrooge95 likes this.
  8. Halfords spare bike gear change cable?
    scrooge95 likes this.
  9. Get the replacement panel, it won't be much time to replace it
    scrooge95 likes this.
  10. I think there are several ways panels die.

    One is corrosion where the positive connection tape from the cells gets eaten away if water gets in. Generally such panels stop working.
    My panels were like this.

    An other way is cracking of the cells. In this case the output of the panel reduces as the current all has to go through a smaller solar cell.. this can happen with vibration or stress caused by installation fixing only corners/edges of flexi panels. People who fit them on boats with ropes through the holes in the edges get total failure flapping in the wind.
    Flexi solar cells are still effectively a layer of glass like silicon bonded to thin metal and plastic. A sharp bend will snap the silicon.
    For instance whacking a car park barrier with the junction box.

    Where panels are connected in series and feature integral shadowing diodes the diodes can maybe short out. In which case you can get full current but lower voltage. Eventually the shorted diodes will burn out and disconnect themselves. In which case the panels will not be as good when partly shaded.

    Overheating. Yes they can get hot in the sun, too hot to touch, but the limit is about the melting point of solder for solar cells. All that happens is they get so hot they stop working because they leak too much current.
    Of course if you fix them down in a frame that does not expand fast enough a panel might buckle and crack.
    Sydney and scrooge95 like this.
  11. I am not sure yet but I may soon be in a position to put a few 100 watt semi flexible solar panels in the For Sale section.

    The way I discovered online to fix the seni-flexible panels down to a surface was with lines of Sikaflex every 30cm across the width of the cell or so with a few blobs at the corners..
    Very strongly attached but no hard fixing points.
    And gaps for water to run out.
    scrooge95 and Lasty like this.
  12. :thinking:

    scrooge95 and paul2590 like this.
  13. For general information, I finally got round to testing my panels. Van had been on hook-up, so the battery was fully charged. Recorded on 19th Oct @ 2.30 with clear sky but sun low in the sky. 2x100W panels mounted horizontally on the van roof.

    Fridge off
    Panels: 20.0V 0.2A 4W
    Battery: 14.4V 0.2A 2.9W
    Fridge: 14.4V 0.1A 1.4W

    Fridge on with door open
    Panels: 18.4V 3.0A 55.2W
    Battery: 14.4V 0.2A 2.9W
    Fridge: 14.4V 3.4A 48.9W

    Open circuit voltage: 20.1V
    Closed circuit current: 5.54A

    I did notice that the fridge demand varied over time and the panel output adjusted itself to match, so the panels clearly had some spare output capacity even with a low sun.
    mikedjames, scrooge95 and Lasty like this.
  14. If you think the panel is dead anyway you should be able to stab a semi rigid panel on the metal strips between the cells with a needle connected to a meter probe, the other end to one of the main panel connections..

    You wont get so far through a glass fronted rigid panel....

    You can always seal the little holes with small dots of waterproof glue/sikaflex if you decided to carry on using the panel anyway.
    Last edited: Oct 20, 2018
  15. While I was at the Motorhome show yesterday, I came across the Photonics Universe stand. Interesting enough they have introduced a new range of Semi- flexible panels with an Aluminium back. They are in the process of updating their catalogue.

    Sent from my iPhone using Tapatalk
    Lasty likes this.
  16. Yes, that’s the range that they are saying I should use to compensate for the roof ridges.
    paul2590 likes this.
  17. I think I’ll wait until spring next year before I contemplate on installing any panels , particularly with new improved products being developed

    Sent from my iPhone using Tapatalk
    scrooge95 likes this.
  18. So as it was a lovely day, thought I’d bring the van out and stick it in the sun. You can see the battery is slightly low so was needing the charge.





    All seems pretty well to me.
    Lasty, mikedjames, Sydney and 3 others like this.
  19. Still looking for a good kit for my install so im ready for the spring.

    Any recommendations. I've spotted this one. Budgeting around £200





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