I have an 18V system and I need to run some fans off of the 18V rail. I've been using 24V fans with PWM control and they work fine (although are slower than their fully rated 24V speed). Now we can't seem to get enough 24V fans to build the next batch (even without PWM, they are out of stock everywhere). Would running a 12V fan on my 18V and never going above 66% PWM work? Or will this fry the 12V fan instantly? Or will it work for a while but with reduced fan life? Short of finding more 24V fans or the world inventing 18V fans, what's the best way here?
I don't have 12V available on the system, nor do I have enough room to add a DCDC that is large enough to handle the current for all of the fans.