Solar cpu fan help

Thread Starter

MarkS

Joined Jan 28, 2014
2
I am building a solar collector out of drink cans, and have a 12v 1.6A fan that I would like to run for ventilation. When I hook it up to a car battery, it runs fine. When I hook it up to a 12v 1.5 watt battery charger, it does nothing.

What size (watt?) solar panel do I need to run the fan? Should I get a different fan that requires less power? I see these on you tube all the time and they all seem to run on really small solar cells? Help!
 

spinnaker

Joined Oct 29, 2009
7,830
That better by an awfully large and / or efficient collector to compensate for the energy lose from a 1.6A fan.

or you are adding an additional solar panel to run the fan?

Just do your math: P=I*E

That is assuming you will get a panel that is really at it's power rating and you have it under ideal conditions. You might want to up size a bit.
 

Thread Starter

MarkS

Joined Jan 28, 2014
2
I didn't know it was a 19 watt fan! So, what would be a good combination for a small solar panel and a small fan? The CPU fan was given to me; I didn't realize it was 19 watts...I don't know much about electricity. As far as the 12v 1.5 watt panel that I have, what size fan could it run? Again, I only want it to run when the sun is out and don't mind if it runs at half speeds when partly sunny. Thanks again for your advice.
 

Bernard

Joined Aug 7, 2008
5,784
I would start with air flow required. With battery operated fan, was there any excess air flow? If 19 W fan is needed, I would aim for a 30 W panel, & if necessary add a soft start ckt. I gather that the main purpose is to collect heat and distribute it with a fan.
 

wayneh

Joined Sep 9, 2010
17,496
I didn't know it was a 19 watt fan!
Well then here's an important fact: The power consumed by a component is the product of the voltage across it and the current flowing thru it, volts x amps, as spinnaker noted earlier (E=voltage in his post). Using Ohms law, you can also show that it is I^2•R.

Pay attention to the comments on air flow. Moving air requires work, so the work done by the fan is determined by how much air you need to move. Many computer fans are 12V and use MUCH less current than 1.6A. Many are 0.1-0.3A and might be fine for your application.
 
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