Running 12v computer fans on a 24v power supply-- just run them in series?

[der_wille_zur_macht]

Agreed, DWZM, on the failsafes. I have two heatsinks (2X24" long) each with 13 LEDs, and active cooling is an absolute.... so I'll probably have two of the small CPU fans on each and possibly another Walmart personal fan blowing across them both.

Another option is to use a thermal fuse on the dimming or power circuit running the LEDs, such that it trips if the heatsink gets above a certain temperature. A few bucks and your LEDs won't burn up if a fan fails.

So two questions.

1) Why did the DC fans work so well on the AC power supply? Seems to me like they'd just get warm and not really move much.

2) What would happen if you connected a 12v fan to a 12v automotive battery....... I have no reason to do that but... the kid inside wonders....

It was getting a hit of power in the "correct" direction 60 times a second. A 12v DC fan connected to a 12v auto battery would run just fine, for a long long time. To the fan, 12v DC is 12v DC. It doesn't care if it comes from a regulated power supply that has 120v AC on the other end, or a battery, or a lemon with electrodes stuck in it!

 

[redfishsc]

Another option is to use a thermal fuse on the dimming or power circuit running the LEDs, such that it trips if the heatsink gets above a certain temperature. A few bucks and your LEDs won't burn up if a fan fails.

I like this idea but I do not know where to find (nor how to use) a thermal fuse---- could you point me in the right direction--- where to look? Basically sounds like a Ranco... but you used the phrase "a few bucks" so I'll assume it's not something quite that jaded.

It was getting a hit of power in the "correct" direction 60 times a second. A 12v DC fan connected to a 12v auto battery would run just fine, for a long long time. To the fan, 12v DC is 12v DC. It doesn't care if it comes from a regulated power supply that has 120v AC on the other end, or a battery, or a lemon with electrodes stuck in it!

Ah, I see. 60 hertz. Makes sense now.