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Solar panel (9v/3.4a) to a PC fan (12v/0.88a)

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Franko

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Looking for some guidance with hopefully a simple question - I have a solar panel that generates 9v /3.4amps in full sun. I want to hook it up to a 12v pc fan that is rated at 0.88amps. Do I need a resistor or anything to prevent any damage to the fan?
Thanks,

Frank
 
No, your solar panel may not even run the fan.

What is the no-load (open-circuit) voltage of the panel in full sun?
 
Indoors, next to a window during partial sun my meter said 1.1amps I hooked up the fan and it was running at what felt like 100% This is the reason I was worried about connecting the fan outdoors in full sun. Outside in direct sun the meter says 3.4amps. Do I ignore the amps, and measure voltage while under load with the fan?
With no fan, the panel shows 9volt, is that open-circuit?
Thanks
 
Indoors, next to a window during partial sun my meter said 1.1amps I hooked up the fan and it was running at what felt like 100% This is the reason I was worried about connecting the fan outdoors in full sun. Outside in direct sun the meter says 3.4amps. Do I ignore the amps, and measure voltage while under load with the fan?
With no fan, the panel shows 9volt, is that open-circuit?
Thanks
Yes. Think of it this way: The battery in your car is capable of delivering 700A to the starting motor. The 1/2A dome lamp is just fine while connected to the battery.

If the panel is only 9V open circuit, I predict that with the fan connected, the panel voltage will drop to about 6V under load. That is why I said that the panel may not even quite run the fan. If buying a panel that should deliver 12V, it should have an open-circuit voltage exceeding 18V...
 
Your car analogy is great. Thanks for explaining that to me. It figures I would have heavy cloud cover today and the panel has 0 output. I want to check that voltage while the fan is going. Thanks for your help Mike.

Frank
 
Most solar panels will have a sticker on the back with full specs. The important value you need is Voc - open circuit voltage.

You cannot get nothing close to full power indoors. You need to get outdoor and direct the panel towards the sun.
 
It's not a commercial panel. I strung several Evergreen cells together that I got awhile back on ebay. Plexiglassed them together and it powers the PC fan well. I just didn't want to burn it out. My wife is tinkering with a Solar air heater and she wanted a fan to help move the air along. Fun little project.
 
You can measure the open circuit voltage. You need to put the panel towards the sun to measure it. Although, if you got 9V at home, I doubt you can get more than 12-14V in the full sun, which should be fine for the fan.
 
Outdoors in direct sun you measured 3.4A from the solar panel but what was the load? The fan or a dead short?
When the solar panel is powering the fan then the current will be much less than a dead short.

You need to measure the voltage and current from the solar panel when it is outdoors in direct sun and powering the fan.
 
Looking for some guidance with hopefully a simple question - I have a solar panel that generates 9v /3.4amps in full sun. I want to hook it up to a 12v pc fan that is rated at 0.88amps. Do I need a resistor or anything to prevent any damage to the fan?
Thanks,

Frank

No problem as long as solar voltage is lower even if current is much more
 
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