Originally Posted by CharlesV
Ok go ahead you guys, NOW whats wrong with this idea?
These 3 and 4 position switches require a series of resistors elsewhere and a bunch of wiring
I'd rather not turn battery
power into that much heat, or light, just to slow a fan.
My vehicle's blower motor
pulls 18 amps on highest speed. I imagine most are similar and the resistors for low medium high are calibrated for an 18 amp motor at 13.6v. a 2 amp fan would likely respond poorly to this method of attempted speed control.
especially when a PWM motor speed controller can be had for less than 10 dollars and require only 4 wires be smushed under set screws to operate.
Heck if the whining of a 13khz LED dimmer was not present or did not bother the user, one could control the fan from super slow to max, fully variable, for under 3$.
21khz, 10 to 40 volts, 15 amp rating, 12$
Some 12v computer fans come with a potentiometer for speed control:
1.3 amps on High, 0.05 amps and silent on low.
This fan did not like fastest speed and battery charging
In the future I will be feeding a PWM signal for speed control via the 4th wire to an Industrial Noctua 3000 rpm
fan. This 2000 rpm
one is IP67 rated:
NF-F12 industrialPPC-2000 IP67 PWM
I have a 1500rpm Noctua pushing air through my fridge condenser. Noise
decreased, duty cycle decreased. Amp draw of fan less than half of 120mm fan provided with fridge. running 24/7/345 going on 4 years next month.