ATHENS 
MY WEATHER STATION, BY DIMITRIS
Location: Peristeri of Athens, Greece
Position: 38 00.58' NORTH / 23 42.04' EAST
Elevation: 63 meters
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ELECTRONIC DESIGN FOR SOLAR PANEL WITH BATTERY FOR RADIATION SHIELD
I make a electronic design for to work a pc fan in a radiation shield. The day it will turn foul speed with 12 volt dc , at the night at half speed with 6 volt dc. For low drop the volt from 12 volt to 6 volt i use one resistor 82 ohm at 1 watt from the type : 12-6/0.075 =80 και 6*0.075 = 0,45w Sollar panell --> charge controller-->battery-->82 ohm resistor to relay for 6 volt dc at fan the night. Solal panel--> 12 volt at fan the day. Solar panel -->i use 160 ohm resistor for drive to relay to cut the contacts to relay at 10 volt dc and down,because before without resistor the relay closed the contacts at 7 volt dc (i make experiments with a power suply 0-30 volt). Fan--> to relay. When it is day with sun solar panel give 12 -16 volt and the relay closed to battery circuit,and solar panel it give power to fan ,the night the when drop the power from solar panel ,open to circuit to relay and give power to fan from the battery . The material it is : A sollar panel 12 volts - 10 watts. A charge controler 12 volt 5 amber. One batery lead acid 12 volt 7,2 or 17 Ah for better results. A pc fan for radiation shield 12 volt 8 x 8 cm. One relay 12 volt. One resistor 150 Ohm,one resistor 10 Ohm at serial for to make total 160 Ohm 1 watt,one resistor 82 Ohm 1 watt. A water proof case for to put inside battery,pcb for the Relay and 2 resistors.

Here it is the electronic design Here it is the PCB,1 relay,3 pcb cable contact,1 resistor 150 Ohm,1 resistor 10 Ohm,1 resistor 82 Ohm Components is is ready over to PCB with soldering iron
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And here the same And here the same Another one photo from the other side
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Here i make a test with two power supply,and i measurement the current mA,and all work fine Click over to photo for to see a video about it
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Another one electronic circuit for better accurace drive the relay

>Here it is the electronic design.With this 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. Here it is the electronic material Here it is ready all the electronic material over to PCB with soldering iron
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The same Here it is from the other side the PCB Here i make a test ans all it is fine
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Here is and two electronic circuits
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