izentrop wrote:Do you need the sun for it to become positive?
Well, that's what I think.
With us from November to January, we really rarely see the sunshine.
I have for example the automatic hatch of my henhouse which is powered by a solar panel which allowed an autonomy of a little over a month. I happened to have to recharge the battery in January. Since I improved the system this does not happen anymore.
Clearly, during heating, any direct solar input, that which passes through the glazing of a room in the house, decreases the need for heating.
What the sun gives, the heating does not provide.
The best gain goes to the glazing which lets solar radiation pass the best and which lets heat out the least.
The curves are for windows facing south, the only ones with a really positive balance.
It's funny what you say about your henhouse, my mother has equipped all her windows with electric shutters.
A small PV per shutter and a battery in the electronics.
I was a little afraid of problems in winter, especially with the 3 shutters under a large awning (not completely opaque), or with the shutters to the north which only see light but never direct sunlight in winter.
So far everything is working wonderfully. Hats off guys!
Like your henhouse, it only works twice a day, but the battery has a reserve for more.
I don't know anything about the battery, but the sensors are 30cm x 15cm at first sight which is not huge either and they are always badly oriented: they are in the corner of the window. At the limit, the lucky ones see the direct sun at the end of the day.
I know a farmer, I haven't asked him yet. I think he can redirect me just in case.
