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Can I use a PC fan as a generator to power an LED? Answered

Is it more complicated than hooking up the + & - power wires on the fan to the + & - wires on the LED and spinning the fan really fast?

I don't know much about the LED I have, but the fan is a 12v BLDC, 0.30A

5 Replies

jeff-o (author)2010-08-19

Oh, it's a brushless DC motor? No, it probably won't work.

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harry88 (author)2010-08-18

yes unless it has a diode

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Jack A Lopez (author)2010-08-18

It can be done. It has been done. Someone, reukpower, has written an instructable on how to do this:

As you suspect, it is more complicated than just hooking up your load to the wires that supply input power to the fan.  There's this pesky  controller board sitting in between you and the wires you want to get to, which are the windings on the motor.  Some cutting, scratching, and  soldering will be required.

I've actually tried this, and I have found that the larger the PC fan is, the easier it is for me to take apart the fan, and make the modifications, without breaking it.  The 90 mm fans are easy, but the 25 mm fans are much more challenging.

I also found this topic:

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peaceoutside.org (author)2010-08-17

I think the circuit board the motor is connected to has a diode or something on it that does not allow current to flow backwards. I can remove the circuit board, but I then loose the controller and it is no longer a motor. I was hoping to have something that could function as both a motor and a generator. I was thinking I might be able to attach the wires that go to the LED directly to the copper windings on the motor itself.

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Re-design (author)2010-08-17

If it generates dc when you spin it then you can use is to power your led.

If you spin it in the right direction it might work.

If you regulate the output so you don't supply it with and overvoltage and don't burn it out.

You could use the fan to charge a battery so that the output is more stable.

How are you going to spin the fan?

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