How can I hook up a 12v computer fan without a computer power supply? (AC adapter?)

[trmiv]

I need to put a fan on my light hood for my fish tank (saltwater reef), and I'd like to a put a nice quiet 12v fan on there. (it currently has a 120v fan that sounds like a dust buster). So, am I correct in assuming that I could just get one of those universal AC adapters that puts out 12v and wire the fan direct to that? Is that safe? Could I run two fans off of one adapter, or would I need to adapters?

 

[MaxFusion16]

Originally posted by: trmiv
I need to put a fan on my light hood for my fish tank (saltwater reef), and I'd like to a put a nice quiet 12v fan on there. (it currently has a 120v fan that sounds like a dust buster). So, am I correct in assuming that I could just get one of those universal AC adapters that puts out 12v and wire the fan direct to that? Is that safe? Could I run two fans off of one adapter, or would I need to adapters?

just make sure the ampere is correct and it'll work

 

[trmiv]

Cool, I think I'll do that. The fan noise from this 80mm 120v AC fan is ridiculous. I nice vantec stealth or something will be much better. Maybe I'll get fancy and mount a fan on each end, and hook it to one of those fan controllers.

 

[ThisIsMatt]

not that the amps are "correct" as that the power supply should put out equal or more amperage than the fan draws

 

[trmiv]

So, since most of those AC adapters are rated in milliamps, I would need a 100 mA AC adapater to power a .10 amp fan, right? I doubt I can find an AC adapter like that, most are at least like 400 mA I think, so that is OK?

 

[etech]

Yes, that will be ok. The power supply must be rated at or higher in current than the load.

Higher is better and recomended.

You'll have to take the plug off of the adapter to wire it to the fan. Make sure you get the polarity correct. I don't think it will hurt the fan to hook it up backwards but it won't run.

 

[trmiv]

So is it OK to hook two .10 amp fans up to the adapter?

 

[JW310]

Originally posted by: trmiv
So is it OK to hook two .10 amp fans up to the adapter?

Yes, as long as the adapter is capable of supplying more than 200mA (0.20 amps).

JW

 

[trmiv]

cool, that's what I'll do, one to push, and one to pull. Both of those will still be quieter than the monster that was on there.

 

[trmiv]

I did it, works great. Hooked up two fans, both are quieter than the one old one. I got an adjustable AC adapter which lets me switch the voltage down, so I can drive both fans at 6v if I need to.

 

[Shawn]

n/m

 

[trmiv]

Just to be sure, it is OK to undervolt fans like this, right? I know people do it in computers all the time. This AC adapter lets me select 12, 9, 7.5, 6, 4.5, 3, and 1.5 volts.

 

[dighn]

yes, just don't go over 12v or you run the risk of frying the fans

 

[trmiv]

cool, no chance of that, only goes to 12v.