Fans for MH

[TWallace]

Thanks Willy and Don for the electrical tips. I'm searching for fans to use on NewEgg now, but it's hard to find how much amperage they use on that site.

 

[DonW]

Thanks Willy and Don for the electrical tips. I'm searching for fangs to use NewEgg now, but it's hard to find how much amperage they use on that site.

They are not good about listing amperage draw. Just find some good ones with real roller bearing. When you get the fans the amperage will be printed on them.

Don

 

[TWallace]

I've noticed some of the fans are adjustable speed (via a controller in a computer). I'm curious how those would work with a 12v DC adapter. Are they still adjustable? If so, how?

I'm considering 4 fans for my canopy I built, probably 120mm (4.72"). Is this too much for 2 250w MH bulbs in a 51" wide canopy? Is 2 enough? Or should I go with 4 80mm fans?

 

[star rider]

most/many of the 80's turn at higher rpm = more noise.
the 120's usually turn lower rpm and are quiet..
the 120's usually move more air more efficiently (hence the lower rpm) there are some available with a dial to adjust speed seperate from the controller on the mother board.
either way works..it's just what you really want.

I personally use 120's for moving air in my stand for my fuge
I also use 2 10's (in/out) on my pc case. you can;rt even hear these fans run

 

[TWallace]

I ordered 4 Arctic Cooling 120mm fans. These ones are very low noise (23db). They have fluid dynamic bearings, and I'm not sure what exactly that is, but I guess they have very long lifespans. It says they use .1 amps, so I should easily be able to power all 4 with one DC adapter.

 

[mmkeeper]

How about something like this.http://cgi.ebay.com/Saltwater-Aquar...4QQihZ013QQcategoryZ46314QQrdZ1QQcmdZViewItem

or

http://cgi.ebay.com/Metal-Halide-Aq...4QQihZ013QQcategoryZ46314QQrdZ1QQcmdZViewItem

 

[DonW]

I ordered 4 Arctic Cooling 120mm fans. These ones are very low noise (23db). They have fluid dynamic bearings, and I'm not sure what exactly that is, but I guess they have very long lifespans. It says they use .1 amps, so I should easily be able to power all 4 with one DC adapter.

A single 500ma supply should be plenty. The controls you mentioned are nice to have. The fans get loud if you have a few and are watching tv. You can drop the voltage to about 8vdc and they get much quieter.

Don

 

[DonW]

How about something like this.http://cgi.ebay.com/Saltwater-Aquar...4QQihZ013QQcategoryZ46314QQrdZ1QQcmdZViewItem

or

http://cgi.ebay.com/Metal-Halide-Aq...4QQihZ013QQcategoryZ46314QQrdZ1QQcmdZViewItem

Those look great I'm going to order some right now. I was looking at the geismann's last night but the $250 was a bit hard to swallow for fans.

Thanks
Don

 

[TWallace]

I got my fans and an 800ma 12v DC adapter. However, the fans have 3 wires (black, red and blue) and the adapter only has two. Which wires do I connect?

 

[TWallace]

Actually I just gambled and tried it out. Black and red worked. I'll just leave blue disconnected I guess.

 

[DonW]

Actually I just gambled and tried it out. Black and red worked. I'll just leave blue disconnected I guess.

Just make sure they are turning the right direction.

Don

 

[burning2nd]

blue is for the computer speed control

 

[TWallace]

Slight problem. My fans claim they use 150 milliamps, and the adapter claims it's 800 milliamps. When I powered them up the first time, all 4 worked. A couple hours later only 2 worked. I unplugged and tried again a few times and got 3 to work. Seems like this adapter is shaky on the amperage output. I do have a second one though, so I guess I'll wire up 2 fans to each adapter. Is this normal?

Do DC fans turn different directions based on which wire connects to which? That would actually be advantageous to me if so. That way I could install both fans on the inside of the canopy pointing out, but have 2 suck air in and the opposite 2 blow air out. I don't want to install 2 inside and 2 outside, would just look odd. The fans can only be mounted one direction, it's a weird design.

 

[TWallace]

I figured out the problem. A wire came loose inside one of the wire nuts. Also I tried reversing the wires to see if the fans would spin the other way. They didn't spin at all when I did this, so I quickly unplugged them. I'm not sure if that can damage the fans or the adapter, but they still work when wired correctly.

 

[burning2nd]

probly not enought power there to damage anything....

the fans have to be redirected so they all face the same direction.... sometimes theres a little arrow pointing the direction..