Powering Pc fans of dc converte, amps question

[lolmannen]

Hi my idea is running 4 fans off a converter. They have a total output of 1.8 amps and I can only find converters with the range of 2.2 amps.
My question is it safe to run smaller amount of amps (from fans) then the converter capacity. Dont want a fire since it is a pc grow
thanks in advanced

 

[PeytonManning]

I wouldn't take any risk with the electronics. I hook up computer fans using old cellphone chargers. Just match up the amps and watts and they'll work fine, no risk of fire

 

[lolmannen]

Not really answering the question. Since my question is more if a 2amp converter always puts out 2amp or does it just have that as a max?

 

[Antics]

This is the basics of what you need.

You have your fans. They are rated in voltage, and amps, or milliamps.

Then you have power supplies.

The power supply voltage for fans should be the same or less than the voltage on your fans.
The power supply amps should be more than the total amps of all fans being powered.

Voltage is just how many volts the power supply supplies. You can power 1 fan, or 100,000 fans. As long as all the fans require the same, or higher voltage it works fine. If you exceed the fans voltage, this will shorten the lifespan of the fan, and possibly cause a fire.

Think of Volts as being Cannabis, and the power supply is the grower. And pretend people are the fans. The grower (power supply) provides the same Cannabis (volts) to all the people (fans) who come to him.

Amperage, or current, is the total power flow available. If a power supply says 2.2 amps, that means you can power any amount of fans as long as the total amps being used by the fans, is less than what the power supply will give. If you exceed the power supply's amperage rating, you will overheat the power supply, and either shorten its life, or it can cause a fire.

Now think of Amperage is Cannabis, and the power supply is the grower, and the fans are the people. If each person (fan) wants 1 ounce (amps), and there are 10 people (fans), but the grower (power supply) only has 6 ounces (amps) left, there's a problem of not enough supply (amps).

 

[Flyinhigh]

I'm not to sure but I'm pretty sure you would be ok with a 2.2 amp converter. Your only .4 amps over. That's only .1 amp per fan.

I'm comfortable in saying that you can overdrive a PC fan .1 amp with no problems. They might get a touch warm, but they shouldn't burn up.

 

[Antics]

I'm not to sure but I'm pretty sure you would be ok with a 2.2 amp converter. Your only .4 amps over. That's only .1 amp per fan.

I'm comfortable in saying that you can overdrive a PC fan .1 amp with no problems. They might get a touch warm, but they shouldn't burn up.

Voltage is what over drives an electronic. If you have 12V fans, and give them 17 Volts, they are being over driven. And the lifespan of the fan will be reduced.

Amps are what the power supply can supply. If the fans draw a total of 1 amp, and the power supply is only rated for 500 milliamps (.5 amps), you are overworking the power supply, and it will likely fail.

You always want amperage ratings to exceed what your electronics need, and voltage readings to match what your electronics need.

 

[Flyinhigh]

Thanks for clearing that up antics, had a mind lapse lol. Early morning and some quality oil will do it everytime.

 

[taura]

Sorry for bringing such an old thread up but I've got a question..I'll be using 2 computer fans for ventilation as well and I've got a modem adaptor (15V ~ 1A output)..and I'm no electrician whatsoever so .. if I put one fan to this adapter, will it work normally or are there any probs? I found the specs of the fans I'll be using, they're Arctic Cooling F12 120mm, 12V (obviously) and they're using 0.24 Amps on 12V...I'm really confused about all this

 

[Antics]

It would work, but the higher voltage will cause the fans to spin faster, will quite possible shorten their lifespan, may create more heat within the motor and wiring, and as a result, may increase the risk of fire.

I would find a better power supply.

 

[taura]

How about if I wire both on the same adapter? Would that make it 7.5V per vent?
This is the ventilator I have, under the Technical Data it says

Voltage	Current
12V DC (Norminal)	0.24A
7V DC	0.14A
5V DC	0.10A

Does that mean the ventilator could properly run at 7V and 0.14A? In that case wiring both on the same adapter would be doable? Darn I need to learn some more about electricity

 

[Antics]

Wiring two fans will not reduce the voltage. Those charts are based on PC power supplies, as they have the ability to provide a number of different voltages.

1 fan or 1000 fans, they will all get 15 volts.
Amperage is the limiting factor on any power source.

You can't even wire the two fans in series, because the resistance of fans changes, and will give each fan a varied voltage.

Be safe, just get another power supply.
But before that, have you considered whether or not these fans will even provide adequate cooling for your lighting/grow combination?

 

[taura]

I'm building a 50x50cm and like 120cm high box..will only do 1 plant at a time, more then enough for my own needs...and I doubt I need any more then 2 120mm fans for in/outake..I just found a 12V 500mA adaptor so I guess that's that for my vents..can I parallel wire them both to the same adaptor or it still wont go? Also do you happen to know whats the yellow wire in the pc vents? Cause I got some old vents with 2 wires but this Arctic one has another yellow wire..is that just for computer purposes like adjusting RPM speed?

 

[Antics]

The 500ma power supply is just barely adequate. .5 amps, vs .48 amps. It'll work, but might run a little warm, otherwise shouldn't be an issue.

Yes, parallel wire for the fans. If you use series wiring, they'll see about 6 volts each, and might not work. If they do work, it will be at a reduced speed, thus reducing CFM.

Yellow wire would likely be for variable voltage, RPM adjusting, sometimes it's for an LED light in the fan, or something similar for PC use. Just go with the red and black

If the two fans running don't control temperature well enough, what you can do is use both fans at the top of your grow box as exhaust/outtake fans (make sure to cut a hole for each fan), and just leave the empty hole for the intake. The negative pressure in the box will naturally draw air in.

I have a small Veg cabinet now, with 4 CFL bulbs, and a single 80mm fan works great to keep it cool. I think it's an 80mm fan, I never measured, it was a spare fan, and it worked so I used it

 

[taura]

Thanks a lot, Ill be using this 500mA 12V adaptor, it should do well I suppose...as for the heat, hopefully it wont be too hot

 

[santb]

Me too!
Anyone out there to help? I wanna run 4 pc fans, connected to a pc 4 channel fan speed controller, connected to one pc power supply, plugged into wall...
Am I missing something? Any reason why this won't work? Or is there some modification to the molex plugs or whatever to make this work without motherboard...
Wanna cut down on wall plugs, fan noise and fire risk(by not using phone chargers etc). Will post this elsewhere also as I can't find anything anywhere..
Cheers in advance.

 

[Faic]

Me too!
Anyone out there to help? I wanna run 4 pc fans, connected to a pc 4 channel fan speed controller, connected to one pc power supply, plugged into wall...
Am I missing something? Any reason why this won't work? Or is there some modification to the molex plugs or whatever to make this work without motherboard...
Wanna cut down on wall plugs, fan noise and fire risk(by not using phone chargers etc). Will post this elsewhere also as I can't find anything anywhere..
Cheers in advance.

You may have found out by now, but you'll need to jumper the green wire to black on the mother board connector on the PSU to have it work via the switch on the back. Or wire a switch into the green to black circuit.