Briefly: Trying to run a small fan with a solar panel to vent air from my shed. If I can make this work, all is well… airflow and such I have worked out. All values below are from my multimeter.
I have a solar panel that puts out 8.7 to 9 volts at 1.8 amps. For testing purposes, I am also using a 9v battery that measures almost identically.
I have two fans marked 12v/0.38a. I can connect one or both of them to the 9v battery and they spin up and work great. They both run full speed (i.e. putting the second fan on does not slow both fans down). If I connect one of these to the solar panel, nothing happens. I try to “kick start” it by spinning it, thinking it needs some oomph to get going, but it doesn’t help. Even a smaller 12v/0.17a cpu fan (which is also known good via the 9v battery) will not move when attached to the solar panel.
I’m stumped. Why would not one but two fans run from a 9v battery measuring around 9v and 1.8a, yet refuse to do a thing when attached to a solar panel showing the exact same measurements?
All help appreciated.
In response to the question below, the measurements from the solar panel are via a multimeter with the panel in full sun. I can take the leads and go from the 9v battery to the panel and back and get almost exactly the same readings within .1 or .2 volts (the battery was a little higher than the panel, but I guess with me running the fans on it to test them, it’s been drained a little and is now virtually identical to the panel’s readings). I have taken similar readings from this panel in full sun in the past where it was pretty much pegged at 9v. So I’m confident about the multimeter readings, which is why this is so baffling. Any other ideas?
Sorry, didn’t answer the question about the rating of the panel. It has no markings on it… this is all about multimeter readings. This is a weatherproof setup that used to have a battery in it and run a string of LEDs at night, so it’s basically a salvaged consumer product.
Great answers and additional questions. I’ll answer them and also, I have puzzling additional information. Thanks everyone who replied so far and anyone else who does!
I was asked if I had checked the voltage at the fan while it was connected to the solar panel:
I’m not sure I fully understand, but I did connect the two, then put the multimeter clips on the twisted wires connecting the panel and fan. The voltage was still nearly 9v. I didn’t check the amps, and can’t now because the sun’s gone down.
I was told the resistance of the fan I am using is 30 ohms and was asked if I’d tested the panel’s current with that included:
I’m not sure how to do this. Do I need a resistor of 30 ohms? I’m an electronics newbie. Additional help is very welcome.
I was asked about the volts/amps from the panel being so high and it was noted that nearly 9v at 1.8a is super high for a panel of this type:
I don’t know what “open circuit voltage” means, however I took my panel readings with the mu
More Pages:
- Solar Power: How Does A Solar Powered Ceiling Fan Work? (10/9/2011)
- Solar Panel: Can You Run A Closed Circuit With A Small Solar Panel And A Small Motor? (10/5/2011)
- Solar Panel: Help With Getting Low Amp Reading With My Solar Panel Array? (11/25/2011)
- Solar Panel: I Want To Convert A Small Fan To A Solar Panel, What Is The Best Way.? (11/1/2011)
- Solar Panel: How Would You Connect A Solar Panel To A Fan? (8/15/2011)
{ 4 comments… read them below or add one }
“I have a solar panel that puts out 8.7 to 9 volts at 1.8 amps.”
Clearly it does not. Is this the rating? or something you have measured? Is the sun shining brightly? Is the panel facing directly at the sun?
ensure the panel face is accurately set or may be the connection are not right.
Have you measured the voltage at the fan while it is connected to the solar panel? It seems there must not be voltage there. Check the connections to the solar panel
It seems highly likely that your solar panel cannot produce the required current that even one fan requires. You say that you have measured the current output of the solar panel. Was this with the panel connected to a resistance of about 30 ohms? This is the resistance of the 12v / 0.38 amp fan. If not, then you must do this first before going any further. If the voltage you get when you do that is much less than the required 9v (minimum figure, I see), then your panel cannot produce the required current. You need a bigger panel – or more of the one you have – or lower wattage fan(s).