[SOLVED] Fans connected to PSU

[Cirices]

That's it. I'm looking for a case and I'm interested in Sentey J20. It has 4 fans incluided. 3 in the front and 1 in the rear. The one in the rear will be connected to de MOBO (B450M Ds3h), but the other 3 fans will go with the PSU. My question is: is a good idea? I mean, when I connect fans to psu i can't control the speed of them. What happens if I let the Pc on for more than 8 hours while fans are spinning at high speed? Will it affect fans' useful life?

 

[gn842a]

You really shouldn't worry about the useful life of fans. You should worry about the noise they make. Fans are cheap and keeping your build cool increases its reliability and useful life. When the fans start to rattle replace them. One downside is cost you should think of a fan as roughly equivalent to a water pump, that is, it would seem that moving air is not big deal but a cubic foot of air is roughly one tenth of a pound and 31 cubic feet per minute is 3.1 pounds of stuff you're moving which is 180 pounds an hour and over 8 hours about 1400 pounds. That's for one five inch fan. If you're operating several you could be moving 5,000 lbs of mass a day. That's work. You'll have to pay for it out of the electric bill.

I'm not saying it will sink your budget but it's more than you think. (And this is why when I converted my house from 24/7 fan operation in each room in summer to window AC the electric bill barely budged. The AC uses more but it cycles on and off. And don't get me started on my electric leaf blower) In a word, respect the work that your fans are doing. If you had to move 5,000 pounds every day you'd know you had a job on your hands. And it doesn't hurt if you want to run the fans day after day for long stretches get some of the best. My Noctua so far has held up for five years, I dunno, 15,000 or 20,000 hours so far.

You can get a fan splitter (run two fans) or a fan controller for multiple fans. Fan controllers will let you control the speed. If you're running your fans off the motherboard you can usually set them to an automatic setting in the BIOS. The automatic setting will spin them up or down as needed.

Personally I never run more than four fans including the one in the psu. And that one controls itself. It comes on....well, practically never. My psu is hugely oversized for the build (long story) so it never warms up.

Greg N

 

[geofelt]

Nice case.
Three 120mm intakes in front and one 120mm exhaust is a good arrangement.
If a fan is connected directly to the psu, it will run at top speed.
I do not know what the rpm spec is. 1200 rpm might be typical .
At tat rate, the fan will be heard, but not really noisy.

If the fans come with both 3 pin and molex connections, you can use either.
If you connect to the motherboard, the motherboard can control the speed.
Usually, you can use a fan splitter to run two fans off of the same motherboard header.

If the fans do not have 3 pin connectors, you can use a voltage reduction adapter to reduce the voltage from 12 to 7 or 5v.

I would have no problem with letting all the fans run at a constant speed.
I find this less distracting than a constant speed change.