Design Solar Panel With Bateries For Fan In Radiation Shield

[weather1967]

Hi all

I make a electronick design (and i thing to build it )for to work a pc fan in a radiation shield

The day it will turn foul turn with 12 volt dc ,at the night at half turn with 6 volt dc

For low drop the volt from 12 volt to 6 volt i use one resistor 80 ohm at 1 watt from the type :

12-6/0.075 =80 και 6*0.075 = 0,45w

Sollar panell --> charge controller-->battery-->80 ohm resistor to relay for 6 volt dc at fan the night.

Solal panel--> 12 volt at fan the day ,

Solar panel -->i use 162 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 batery 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 .

Tha material it is

A sollar panel 12-16 volt 5 watts or 10 watts for better results

http://www.maplin.co.uk/Module.aspx?ModuleNo=96861#features

A charge controler 12 volt 5 amber

http://www.maplin.co.uk/Module.aspx?ModuleNo=37774

one batery lead acid 12 volt 2,2 Ah

http://www.batteries.gr/product.asp?catid=2659

a pc fan for radiation shield 12 volt 8 x 8 cm

http://elektronik.gr/eshop/index.php?main_...42f4cf3d69766d9

one relay 12 volt 2 contacts

http://elektronik.gr/eshop/index.php?main_...oducts_id=16973

a water proof case for to put inside batery,charge controler,pcb with relay and 2 resistors

http://www.emimikos.gr/shop/product.php?pr...=505&page=1

I have and one design ,but i am sorry, i am not good to design ,i hope to understand the design.

[I can't believe it's not better]

It seems like quite a complicated design. If I did this I would try to match the size of the solar panel, to the capacity of the battery. So that it was impossible to make the battery go higher than ~14.5V with the fan running.

Very occasionaly you could give the battery an equalising charge by disconnecting the fan and let it go to ~15V for a short while.

Also I would let the fan run full speed overnight (though it would slow down with lowering voltage) just by using enough capacity (Ah) so that the battery wouldn't drop below ~11.5V.

But yeah, you need a way to stop the battery from discharging too low and causing damage, (if there was a very dull cloudy day/s, like in Wales) so I would make a circuit that shuts off the power when the battery is very low <~11V using a simple circuit with a zener diode.

Even better would be to make a simple zener diode circuit that limits the voltage to the computer fan at ~12V, because that is it's design rating, maybe.

[weather1967]

Νο complicated it is a very easy design no regulator for low voltage 6 volt at night only serial resistor .If you use 10 watts solar panel it will be better for fast charge battery .

If you use the foul speed at night fan ,it is not good idea because you have wrong temp data. Davis weather station fan at night it turn to half speed.

Serial resistor at fan the night i beleive it is better because cut the voltage at 6 volt ,and battery life is to long ,no circuits with manny electronick components ,just simple two resistors and one relay B)

[weather1967]

I make a better picture electronic design.

[I can't believe it's not better]

I think I understand now, with a clear circuit diagram. It is quite simple after all (I think - it's a long time since I did any electronics).

If the fan was running at full speed at night, it would give a wrong temperature, because it would add the small heat from the fan. The fan is blowing into the radiation shield? Or is it another reason?

[weather1967]

I think I understand now, with a clear circuit diagram. It is quite simple after all (I think - it's a long time since I did any electronics).

If the fan was running at full speed at night, it would give a wrong temperature, because it would add the small heat from the fan. The fan is blowing into the radiation shield? Or is it another reason?

Tha fan sucks air from sensor ,and put out from the roof the hot air look the radiation shield design .

[weather1967]

Today i build the pcb with components

Resistor i use one 150 Ohm + one 10 Ohm at serial for to make total resistor 160 Ohm for drive to relay and one 82 Ohm from battery to relay .

[weather1967]

Ηi again i up load a video about test the electronic circuit , with two power supply 12 volts,and all work fine .I measurement the current mA with two multimeters.

http://www.youtube.com/watch?v=_VCyMmtCSvM

[The PIT]

Okay your challenge now is to get one to work with the davis fan. You need to get the voltage down to 1.5V