Adding a Fan

I'm trying to upgrade my printer with another cooling fan and I've recently purchased a 40mm 12v fan to mount on my Huxley. However, I've found that the 'fan' connection on the Melzi board supplies 19v. I've had a few ideas about what to do with regards to this:

a) Use a voltage divider to bring the 19v down to 12v. I guess this isn't such a great idea as it's quite a large voltage drop and I'm supplying a load?

b) Would setting the fan speed in Slic3r to less than 100% (say, 60%) effectively reduce the voltage for me using PWM?

Are either of the above options viable for the fan and safe to use? Does anyone have any other suggestions?

Thanks

Edited 1 time(s). Last edit at 07/06/2014 07:33AM by PatrickT.

a) Perhaps you mean using a voltage regulator, such as a 7812T. This is a viable option. If you want to add another consumer (say yet another fan), you should also add a small heatsink to the regulator.
b) Will work fine.
Please note that some fans withstand 19V without problems, but is hard to say which ones

Quote
PatrickT
b) Would setting the fan speed in Slic3r to less than 100% (say, 60%) effectively reduce the voltage for me using PWM?

If your fan is connected in a way allowing PWM, yes.

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Reading around I'm pretty sure it's PWM. Anyway, I ended up going for it and setting it to 80% in Slic3r - this seems to work fine. The fan appears to cope well and it's doing the job judging by some test prints.

Thanks for the advice.