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General => General Technical Chat => Topic started by: Simon on May 29, 2011, 02:17:59 pm

Title: solar cells and water (rain)
Post by: Simon on May 29, 2011, 02:17:59 pm
Well as some may remember i have me a nice pack of 40 x 1.8W solar cells that yes i have still not got around to using. My main obstacle I think is what to cover them in ? I'm worried that perspex may discolour and I'm not sure i want to use glass although I suppose in the end I'll go get some perspex.

A thought did occur to me though: So what if the cells get wet ? does water damage solar cells ? I mean once the sun comes out again they'd dry off pretty nippy. I presume that as I'm the only nutter to consider this, water on solar cells is NOT a good idea ?
Title: Re: solar cells and water (rain)
Post by: sacherjj on May 29, 2011, 03:59:00 pm
I've not seen solar cells for mounting that didn't have a clear potting or covering.  That should have no problem with water.  I would be concerned if you put up a raw cell, due to any impurities in the rain depositing on the raw cell.  It seems like it could effect it over time.
Title: Re: solar cells and water (rain)
Post by: Simon on May 29, 2011, 04:11:34 pm
yes that would be one drawback - acid rain
Title: Re: solar cells and water (rain)
Post by: Simon on May 29, 2011, 06:20:59 pm
Is there a transparent potting compound I could use ?
Title: Re: solar cells and water (rain)
Post by: Zero999 on May 29, 2011, 07:35:43 pm
Why not use a varnish or lacquer?
Title: Re: solar cells and water (rain)
Post by: Simon on May 29, 2011, 07:40:17 pm
well not sure about varnish, If I'm covering them I might as well go the full hog and make them mechanically protected too. After all commercial panels are potted essentially. Of course there was that plan to give them some air space and air cool them so maybe I should just get some plexiglass
Title: Re: solar cells and water (rain)
Post by: Mechatrommer on May 29, 2011, 08:10:34 pm
i vote for glass or perpex. permanent cover will make modification impossible to solar panels.
Title: Re: solar cells and water (rain)
Post by: Fraser on May 29, 2011, 08:31:39 pm
Not persex. Use clear Polycarbonate sheet or even the clear (untinted) cellular polycarbonate that is used for a conservatory roof.

In manufacturing even fingerprints on the unprotected cells are a problem and cotton gloves are worn. IMHO rain in direct contact with the cells will produce contamination of the cell material destroying it, and electrolytic corrosion of the contact strip surfaces (rain is quite dirty and not pure water).

In three words....keep them dry  ;)

 
Title: Re: solar cells and water (rain)
Post by: Vertigo on June 13, 2011, 08:52:26 am
if they are going to be exposed to rain, also consider: snow, hail and other things falling from the sky such as bird crap.
which i believe is more acidic then acid rain.
whatever u use, it might be good if it can stand up to aggressive cleaning materials, cuz that bird crap can be hard to get off.

Title: Re: solar cells and water (rain)
Post by: bilko on June 13, 2011, 12:27:11 pm
Your local glazier should be able to supply you with toughened glass, its not that expensive and you can get it cut to exact size
Title: Re: solar cells and water (rain)
Post by: sacherjj on June 13, 2011, 02:15:34 pm
And one other thing to consider if how to keep the temperature down.  I believe it is still the case that cells performance drops pretty bad with increases in temperature.  Not sure if this is done in commercial cells or not.  I guess there could be a problem with spiders and such, getting in and mucking up the works.  :)
Title: Re: solar cells and water (rain)
Post by: scrat on June 13, 2011, 04:23:36 pm
And one other thing to consider if how to keep the temperature down.  I believe it is still the case that cells performance drops pretty bad with increases in temperature.  Not sure if this is done in commercial cells or not.  I guess there could be a problem with spiders and such, getting in and mucking up the works.  :)

I agree. Keep them closed. You can still take them cool by mounting on a conductive panel and making it dissipate.
Title: Re: solar cells and water (rain)
Post by: hannobisschoff on June 14, 2011, 01:55:37 pm
if they are going to be exposed to rain, also consider: snow, hail and other things falling from the sky such as bird crap.
which i believe is more acidic then acid rain.
whatever u use, it might be good if it can stand up to aggressive cleaning materials, cuz that bird crap can be hard to get off.


Nice thinking there. I would've forgotten about it.
Title: Re: solar cells and water (rain)
Post by: scrat on June 14, 2011, 02:22:43 pm
if they are going to be exposed to rain, also consider: snow, hail and other things falling from the sky such as bird crap.
which i believe is more acidic then acid rain.
whatever u use, it might be good if it can stand up to aggressive cleaning materials, cuz that bird crap can be hard to get off.


Nice thinking there. I would've forgotten about it.

Maybe half of the world would've forgotten about the snow, at least!
Title: Re: solar cells and water (rain)
Post by: Mechatrommer on June 14, 2011, 03:27:31 pm
but not the bird crap, and spiders
Title: Re: solar cells and water (rain)
Post by: Sionyn on June 17, 2011, 02:44:11 pm
Diy Solar Tracker (https://www.youtube.com/watch?v=UufteaRhnPI#)