Simple voltage limiter
I recently added a 180MM computer muffin fan to my intake window.
The fan, a silverstone FM181 which employs a variable speed 10k ohm potentiometer, has an operating voltage from 5v to 13.2v.
http://silverstonetek.com/product.php?pid=344&area=en
Well yesterday afternoon, I finally got it mounted, and I ran it all night very happy with its performance and effectiveness and no issues, but now that the sun is up and it is receiving voltages well over 13.2, the hub motor is getting extremely hot.
I have other fans which have sub 15v ranges that do not get hot, nor seem to have reduced lifespans, which is why I decided to employ this fan for this task outside its design parameters.
So what are my options to restrict charging voltages fed to this fan, yet not also handicap is maximum output when the sun is down, if possible. When I most need this fan, in summer, I have a solar surplus, so I am not too concerned about wasting electricity, I'd just prefer to allow it to goto full speed at night when no charging voltages are present.
I've gone to considerable effort to make a tight fitting 3 fan shroud for this fan( and 2 120mm fans) for maximum positive air displacement, so just going back to 3 noisier 120mm fans is not an option I wish to pursue. Unfortunately the few other 180mm fans available do not have a very high cfm rating, and that was a major consideration when acquiring this particular fan. It also is the biggest fan which can fit in my window without being restricted.
It also moves a good amount of air silently for only 0.05 amps on the lowest speed, which is one reason I wanted it.
If I lower the max speed then the hub cools down but is still pretty warm.
The 2 other fans share the same power source and fuse. I can add something inline like a diode or 2 to drop the voltage, but prefer something non bulky or just plain wasteful, if such an option exists.
The fan, a silverstone FM181 which employs a variable speed 10k ohm potentiometer, has an operating voltage from 5v to 13.2v.
http://silverstonetek.com/product.php?pid=344&area=en
Well yesterday afternoon, I finally got it mounted, and I ran it all night very happy with its performance and effectiveness and no issues, but now that the sun is up and it is receiving voltages well over 13.2, the hub motor is getting extremely hot.
I have other fans which have sub 15v ranges that do not get hot, nor seem to have reduced lifespans, which is why I decided to employ this fan for this task outside its design parameters.
So what are my options to restrict charging voltages fed to this fan, yet not also handicap is maximum output when the sun is down, if possible. When I most need this fan, in summer, I have a solar surplus, so I am not too concerned about wasting electricity, I'd just prefer to allow it to goto full speed at night when no charging voltages are present.
I've gone to considerable effort to make a tight fitting 3 fan shroud for this fan( and 2 120mm fans) for maximum positive air displacement, so just going back to 3 noisier 120mm fans is not an option I wish to pursue. Unfortunately the few other 180mm fans available do not have a very high cfm rating, and that was a major consideration when acquiring this particular fan. It also is the biggest fan which can fit in my window without being restricted.
It also moves a good amount of air silently for only 0.05 amps on the lowest speed, which is one reason I wanted it.
If I lower the max speed then the hub cools down but is still pretty warm.
The 2 other fans share the same power source and fuse. I can add something inline like a diode or 2 to drop the voltage, but prefer something non bulky or just plain wasteful, if such an option exists.
