Hi again
I make a electronic circuit with 2N2222 tranzistor, and CA3140E microcircuit, i drive to relay with better accurace,with trimmer i tuning at how voltage i want to drive the relay.
All it is the same with other project ,except the relay circuit
Fan turn the day with full speed ,and the night at half speed
Here i have more photos at down side ,and the electronic design
http://users.otenet.gr/~meteo/project_solar-panel-electronics.html