Electrical connection question: Multiple PC fans

reef_doug · 04/09/2007, 07:14 PM

I am wanting to hook up 3 or 4 EA x 120mm Vantec Stealth Fans to be powered by one AC/DC 12v Adapter.

The fans are 12vdc, 0.08A, and .96w ea.

Should I hook these up in Series or Parallel?
What size 12v AC/DC adapter do I need? (mA and/or wattage)

Thanks
Doug

artful-dodger · 04/09/2007, 08:57 PM

hook them in parallel.

any 12v adapter will work...the fans are very low draw (is it really .08 amps??? the computer fans I've used are closer to .1 to .2 amps.) so 4 of them will probably be less than the rating on whatever adapter you find.

the best adapter (unless you are going to recycle an extra cell-phone charger) is one that gives you the choice of multiple voltages. I use an adaptor I found at Amazon--Coby 800mA Adaptor (part # CA-989) that gives you a simple switch to choose between 1.5, 3, 4.5, 6, 7.5, 9 or 12 volts. The speed of the fans varies with the voltage (the wonders of direct current!) so you can better control how much cooling you get. (I think you could get the same effect on a more DIY basis with a potentiometer/variable resistor.)

reef_doug · 04/10/2007, 12:57 AM

Thanks.
I currently have a variable Coby 12vdc 300mA and it works great for one fan. When I hooked 2 fans in parallel, the speeds diminished by about 30%. I double checked... it is on 12v.

I'm thinking to get a 1200mA adapter, would this allow 4 fans to have the speed of 1 fan at 300mA? Do I need to be concerned with watts? (each fan at .96w).

(I don't know if you can just add up amperages and/or watts, my electronics mathematics is not good).

A couple vendor sources on the internet confirmed the 120mm Vantec Stealths are 0.08A and .96w.

reef_doug · 04/11/2007, 12:28 AM

^^^

luca.sl · 04/11/2007, 01:46 AM

reef_doug
your fan (i see the specs) really use only 80mA to work, so the total 4 fan need a current of 80x4=320mA... very strange if you use two in parallel, the speed slow to 30%, but the voltage has to be down also.. may be your supply has problem....
bye
LUCA

04/09/2007, 07:14 PM	#1
reef_doug Premium Member Join Date: Jul 2006 Location: Hesperia/Apple Valley Posts: 3,814	Electrical connection question: Multiple PC fans I am wanting to hook up 3 or 4 EA x 120mm Vantec Stealth Fans to be powered by one AC/DC 12v Adapter. The fans are 12vdc, 0.08A, and .96w ea. Should I hook these up in Series or Parallel? What size 12v AC/DC adapter do I need? (mA and/or wattage) Thanks Doug __________________ "If you have more than one tank in your livingroom, you might be a reefneck" Current Tank Info: 180r SoCal Creations, 75g SCC1M Sump, WM EcoBAK, NextReef SMR1, TropicMarin Salt, ACIII, 3x250w HQI Phoenix 14k, 2x140w Super Actinics, ATi BM250, Eheim 1262, Tunze 2x6100+7095, Tunze Osmolator, 6 stage RODI w/ Spectrapure MaxCap

04/09/2007, 08:57 PM	#2
artful-dodger Registered Member Join Date: May 2004 Location: Highlands Ranch, Colorado Posts: 3,011	hook them in parallel. any 12v adapter will work...the fans are very low draw (is it really .08 amps??? the computer fans I've used are closer to .1 to .2 amps.) so 4 of them will probably be less than the rating on whatever adapter you find. the best adapter (unless you are going to recycle an extra cell-phone charger) is one that gives you the choice of multiple voltages. I use an adaptor I found at Amazon--Coby 800mA Adaptor (part # CA-989) that gives you a simple switch to choose between 1.5, 3, 4.5, 6, 7.5, 9 or 12 volts. The speed of the fans varies with the voltage (the wonders of direct current!) so you can better control how much cooling you get. (I think you could get the same effect on a more DIY basis with a potentiometer/variable resistor.) __________________ "In matters of style, swim with the current; in matters of principle, stand like a rock." -- Thomas Jefferson Current Tank Info: 140g RR Oceanic "Ultimate" mixed reef, 37g softies, 40g RBTA tank, 65g FOWLR, 40g breeder frag, and (of course) a 29g QT! ...next up is a 240g! (Gotta go to K-Mart and buy a life...)

04/10/2007, 12:57 AM	#3
reef_doug Premium Member Join Date: Jul 2006 Location: Hesperia/Apple Valley Posts: 3,814	Thanks. I currently have a variable Coby 12vdc 300mA and it works great for one fan. When I hooked 2 fans in parallel, the speeds diminished by about 30%. I double checked... it is on 12v. I'm thinking to get a 1200mA adapter, would this allow 4 fans to have the speed of 1 fan at 300mA? Do I need to be concerned with watts? (each fan at .96w). (I don't know if you can just add up amperages and/or watts, my electronics mathematics is not good). A couple vendor sources on the internet confirmed the 120mm Vantec Stealths are 0.08A and .96w. __________________ "If you have more than one tank in your livingroom, you might be a reefneck" Current Tank Info: 180r SoCal Creations, 75g SCC1M Sump, WM EcoBAK, NextReef SMR1, TropicMarin Salt, ACIII, 3x250w HQI Phoenix 14k, 2x140w Super Actinics, ATi BM250, Eheim 1262, Tunze 2x6100+7095, Tunze Osmolator, 6 stage RODI w/ Spectrapure MaxCap

04/11/2007, 12:28 AM	#4
reef_doug Premium Member Join Date: Jul 2006 Location: Hesperia/Apple Valley Posts: 3,814	^^^ __________________ "If you have more than one tank in your livingroom, you might be a reefneck" Current Tank Info: 180r SoCal Creations, 75g SCC1M Sump, WM EcoBAK, NextReef SMR1, TropicMarin Salt, ACIII, 3x250w HQI Phoenix 14k, 2x140w Super Actinics, ATi BM250, Eheim 1262, Tunze 2x6100+7095, Tunze Osmolator, 6 stage RODI w/ Spectrapure MaxCap

04/11/2007, 01:46 AM	#5
luca.sl Registered Member Join Date: Mar 2007 Location: Italy Posts: 21	reef_doug your fan (i see the specs) really use only 80mA to work, so the total 4 fan need a current of 80x4=320mA... very strange if you use two in parallel, the speed slow to 30%, but the voltage has to be down also.. may be your supply has problem.... bye LUCA