Arduino and Solar Energy

Hi everyone!
Just to inform any of you willing to build a thermal solar collector with simple materials, controlled by Arduino.
Project ARETHA intends to provide instruction and sharing experiences on this subjects.
We have also launched a funding campaign to build one ARETHA with recycled material in Sicily, see:
ARETHA Project - Solar collector made from recycled materials and Arduino. | Indiegogo
I can provide any other information about this project. It is an open one.

That is a nice use of arduino and right in the centre of what it was meant for.

At the moment I have one which has been running continually off the usb of a raspberry pi, which is logging to file the usb-serial messages from it. Power supply for both is
large solar photovoltaic > solar battery controller > car battery > buck pwm at 5V > computers
I butchered a mains plug to get an earth ground from the wall to the 0V black of the computers and battery. Best not to let those float. The car battery is probably a bit big for running an arduino but having more than a week of computer running does no harm.

When not charging the scrap car battery, the large photovoltaic goes to "overflow" to a grid tie inverter. Ask if you want more info on any of these.

This week I've been dabbling with an i2c lcd screen which I'll be using in my own nonstandard arduino based hot water tank controller.