Thursday, October 21, 2010

Timber!

Trees.  Good for the environment but no good for your solar power.

In the winter, my panels used to get shaded by a bunch of trees near by, as the Sun made its low 15 degree arc above the horizon.

Well, now a big gap has opened up in the horizon!  For years, there has been this nearly dead fir tree in someone's garden, on the other side of the courtyard, blotting out the late morning sun in our garden.  But yesterday, unannounced, a van turned up with some tree surgeons and a massive shredder.

It took about a day and half, but the dead tree was gradually chopped up and shredded, leaving a big new window on the horizon - and no doubt a few extra welcome Watt-hours on the clock this winter.

Time lapse over two days

Sunday, October 3, 2010

Dodgy Plastic Panels...

Hmmm... I'm glad I sold off most of the plastic framed amorphous panels.  One of the two remaining ones broke the other day.  It suddenly went open circuit.  Rather than bin it, I decided to take it to bits to see how they were put together.

The black caps on the back hide a load of small screws that hold the thing together.  Luckily, the sealant that was under the cover wasn't glue so I could easily take the back off of the panel.  Under the silicone sealant on the positive lead, the end contact on the glass had broken off and the red wire came away with the sealant it was embedded in.  This was possibly from thermal stress as I remember hearing the frames creaking in the sun and shade. 

There was a thin stub of copper poking out from under the laminate. The panel seems to be made from a sandwich of two plates of glass (presumably with one having the amorphous cells evaporated on to it). I just about managed to solder a thin wire on to this and then joined it to a new thicker wire and potted the whole thing in silicone sealant again before screwing the back on.  How long will it last?  Who knows...

To save propping up the thing on a garden chair, I made up a rear leg, just fixed on with the usual brass hinge.

Now that it's getting darker in the days, it's actually better to have the amorphous panels at a shallow angle as they produce more power from just "seeing" more diffuse light from a bigger proportion of the sky than if you aim them at the non-existent Sun.