over clocking my stir plate?

MrMeans · Oct 16, 2011

Ok so all I know about electricity and electronics is that are full of magic and voodoo. I have a stir plate I built out of a 12v computer fan and some neodimium magnets. I am getting a bit of stir action with 2L of water or when making cold brewed coffee but I was wanting to get a little more oomph out of it. What would the ramifications be if I upped my voltage to 14 or 16 volts with a different adapter to try and get a bit more power from the cheap computer fan?

Golddiggie · Oct 16, 2011

Don't do it unless you have a fire extinguisher on hand. Far better off to get a higher RPM fan to use. Since fans are so damned cheap, I think it's foolish to try to 'overclock' one.

ozzy1038 · Oct 17, 2011

As long as there is movement of the solution, that is all you need to make starters. You don't need a vortex from top to bottom for it to be effective. If you do want more "oomph" get another fan as suggested.

kh54s10 · Oct 17, 2011

It is not the voltage but the mili-amp output of your power supply. Look at the label and if it says 300mA, look for on that has 500mA or 800mA. You can also add a rheostat, if you didn't already to control the fan speed. I had the opposite problem. I tried a 500mA power supply and it would turn the stir bar too fast and it would get thrown to the side of my flask. I installed a 300mA supply - no problems now.

You also just need a small dimple on the surface to have enough stirring going on. You don't need a great big tornado going in there.

DrJerryrigger · Oct 17, 2011

Changing the voltage will increase the speed your fan moves at and it's unlikely 14-16V would cause problems with a 12V fan (though officially I'm not recommending it). But if the fan is already being pushed hard due the the load of the bar, then it may cook the fan's motor quite fast. It all depends what the limiting factor is here.
But as kh54s10 said, your power supply may also be the limiting factor.

The best thing to do would be to get a more powerful fan (more amp/watt) and a matching power-supply, and set it up with a pot so you can control it.

audger · Oct 17, 2011

Changing the voltage will increase the speed your fan moves at and it's unlikely 14-16V would cause problems with a 12V fan (though officially I'm not recommending it).

i agree with this. another volt or a few is unlikely to damage anything.

probably the better way to increase the speed would be to remove the fan blades from the hub. since you arent trying to move air, they are just causing drag that can be eliminated. less drag and less rotational mass = increased speed. you should have a rheostat or PWM to controll it though, because doing this may increase the speed too much, so you should have a way of dialing it down just in case that happens. also be careful not to unbalance it.

nutty_gnome · Oct 17, 2011

I had this problem. I had a few different scavenged power supplies that I tried. I had one at 3 volts and low amps which was not enough, one at 5 volts which was marginal and one at 19 volts 3 amps which cooked the fan. I finally found a 12 volt 1 amp plug in converter and test runs with the potentiometer suggest that this is what I need for my 2L flask. Kepp looking for plug in chargers of various ratings. My dollar store has lots of chargers for cheap that might be suitable.

MrMeans · Oct 18, 2011

I may try the fan blade thing. Right now I have an adjustable power supply and a potentiometer on it. It gets liquid moving with an ok demple. This is more of a thing I was asking about because I made some cold brew coffee yesterday and I had to manually stir in a lot of the coffee. I built this thing to aide in my enjoymeent of not doing a damn thing. Thanks for the suggestions guys.