Running Fans Above 12 Volts?

SilenceOfTheFans · Post by **SilenceOfTheFans** » Wed Aug 20, 2008 3:12 pm

is it ok to run 12 volts fans above 12 volts? for example 16 volts or so
i want to use a pc fan to aircool one of my brushless radio controlled monster trucks

without having to use an additional battery for the fan
im guessing it will decrease the life of the fan but by how much? it doesnt need to last 10000 hours or however long like a pc fan, 100 hours would be enough (tho more would be nice)

Thanks

Vicotnik · Post by **Vicotnik** » Wed Aug 20, 2008 3:34 pm

It will decrease the lifespan of the fan a bit, but it will work fine. If you don't want to run the fan out of specs then you could build a simple fan controller.

SilenceOfTheFans · Post by **SilenceOfTheFans** » Wed Aug 20, 2008 3:36 pm

the extra volts will increase cooling which is important, and i'd like to keep the weight down, i just need to know whether it will reduce the lifespan to like 100 hours or less than one lol wouldnt want it to fry before i get outside

Thanks

Vicotnik · Post by **Vicotnik** » Wed Aug 20, 2008 3:42 pm

I know many 12v fans are rated for up to 14v so 16v is not that much over spec. I think it will be fine, but it really depends on the fan. It will not reduce the lifespan by a factor of 100 though.

widowmaker · Post by **widowmaker** » Wed Aug 20, 2008 5:50 pm

It will definately run hotter though. I'm not sure if anyone has ever analyzed the heat in the fan hub where there's no airflow, but any extra heat is obviously a bad thing.

SilenceOfTheFans · Post by **SilenceOfTheFans** » Wed Aug 20, 2008 5:56 pm

it will probably only be running for about half an hour at a time, an hour max, then will have atleast an hour to cool, so shouldnt be too bad right?

kaange · Post by **kaange** » Wed Aug 20, 2008 5:57 pm

You could just add an inline resistor to lower the voltage across the fan.

If you can find the current rating for the fan, just divide 4 by that and you will get the resistor value required.

Eg fan rated at 0.25A => 4/0.25 = 16 Ohm resistor needed. You won't need to worry too much about the power rating of the resistor unless your fan draws a serious amount of current (resistor in the example needs to be rated 16 Ohm * 0.25A * 0.25A = 1W or 4V * 4V / 16 Ohm = 1W)