Questions about running axial fans / DC power

[Bedlam]

Hello! I am Bedlam, nice to meet you all, you all seem very knowledgeable.

Down to business - I don't remember reading where, but somewhere on these forums i believe there was a guide to using cell phone chargers to power axial fans or pc fans or something. I have a LG charger that came with my EnV2, model STA-U32WS.
It says Input: 100-240V~50/60Hz 0.2 A
Output: 5.1V-.-.-0.7A

I don't see an indication of AC or DC current anywhere on this charger, and since the charging port on my phone broke, this charger is useless to me right now. I was hoping to save money and use it to power a fan or two strictly to cool my light down with a cool tube.

1.) Can I use my phone charger to power either one or two cheap fans enough to cool a 400w HPS light?
2.) If so, what kind of fan(s) should I use? Anyone have experience with this type of setup, or where to get this type of fan?

Thank you all. I'm trying to get my growbox together within the next week, so I can hopefully 12/12 my way from seed to harvest before christmas break.

 

[hoosierdaddy]

That charger is putting out DC power. It can handle a DC motor(s) of up to a total of .7 amps.
The DC pc fans that you would use will have an amperage rating on them. If the fan says .7 amps or less, then the charger can run it fine. Two DC fans with ratings of .3 amps apiece or less would also be within the limits of the charger.

When running two DC fans, make sure you have them running the correct direction. DC motors will run in reverse when you switch the terminals.
Tie both of the positive leads together and both negative leads together, and then tie them to the charger leads. If wrong direction, simply switch leads of the charger.

Welcome to ICMag, btw....

 

[Bedlam]

thanks HD,
I read something about wiring in parallel, and wiring in a series? i seem to remember that with one, the amperage was split amongst all fans, and with the other, each fan got the undivided, full amperage. i know you just told me that the fans must be .3 amps each, but for some reason i think i remember reading about being able to hook up two .7 amp fans at full power off this one charger.

am i being ignorant?

 

[hoosierdaddy]

No matter how many fans there are, the total amount of listed amps is what you look at.
If you have two fans that show 500ma rating (btw...ma means "milliamp" or 1/1000 of an amp) then you have a total power requirement of 1000ma or 1 amp. The charger than you have is only rated for 70% of that, being it is a .7 amp unit. It will not be able to effectively run two .5 (or 500ma) fans.

If I have a charger that says it is rated at 5 amps, then I can keep adding up fans until I have reached the limit of ~5 amps.
If my fans are using .5amps each, then I can effectively run 10 of them on the 5 amp supply.

When wiring up DC power, you want to "daisy chain" the wires together. Which means doing like I said, tying all the positive leads together into one wire, and connecting it to the +positive side of the transformer (charger). And all the neg leads to the -neg side of trans. This is called running power in parallel, where the leads from each device come directly back to the power source.

The other method of wiring, called in series, runs the leads from each device to the next device and finally to the power source. This is done with AC lighting applications.

I don't worry too much about giving out info on DC power applications, as they are normally low voltage issues and lives are usually not ever in peril.
But, I would like to make the disclaimer that I AM NOT A LICENSED ELECTRICIAN!

 

[Bedlam]

hey thanks man this really clears it up for me. so, would buying two of these:

http://www.buyextras.com/medc24v120x1.html

and hooking them up to this cell phone charger be an effective way to vent the cool tube, even with the resistance from a few feet of ducting? they are 350 milliamps each, so that totals .7 amps right?

EDIT: also, if this is a viable option, how would I install these fans into the duct? or the cool tube? i plan on using a pyrex bake a round tube, so these fans would not fit directly in the tube.

 

[hoosierdaddy]

Yes, you can run those fans with that charger.

There are many ways to accomplish the tasks you will need to. And there is a multitude of reading that one really needs to do to get familiar with what folks are doing. It is going to take some investment from you to get all the answers you are looking for. It is easy to keep asking the questions until your cab is putting out buds, but not many here are going to spoon feed you that far. They too have made the required investment.
You will never be refused help here, but if you don't do at least some research on your own, the help will drop off fast, trust me.

I would bolt both fans together and place them at the end of your duct. Then afix it to the end of the duct as best you can with aluminum tape. (I recommend not using duct tape for this)

 

[FreezerBoy]

I'm even LESS an electritian as Hoosier but, as I understand it, Series means if one unit fails the whole chain fails. In Parallel, one unit stops, the others keep going.

 

[Bedlam]

Yes, you can run those fans with that charger.

There are many ways to accomplish the tasks you will need to. And there is a multitude of reading that one really needs to do to get familiar with what folks are doing. It is going to take some investment from you to get all the answers you are looking for. It is easy to keep asking the questions until your cab is putting out buds, but not many here are going to spoon feed you that far. They too have made the required investment.
You will never be refused help here, but if you don't do at least some research on your own, the help will drop off fast, trust me.

I would bolt both fans together and place them at the end of your duct. Then afix it to the end of the duct as best you can with aluminum tape. (I recommend not using duct tape for this)

i don't expect to be spoonfed at all, and i appreciate the help. i just couldnt for the life of me find anywhere that would tell me if my charger was dc, and also it says .2A on it in one place and .7A on it in another. i could follow the concepts demonstrated in the phone-charger-dc-fan guide but did not know how to interpret the information on my charger.

 

[hoosierdaddy]

The input information of the charger tells you what is needed to power up the charger itself. Yours is telling you that it will work with any AC voltage from 100-240 volts and can handle voltage being produced in 50 or 60 hertz cycles.

Hz (hertz) cycles are basically how many pulses the electric charge pulses in a minutes time. USA produces AC electricity at 60 Hz and Mexico at 50 Hz.
I think Europe may also be a 50 Hz area. (shrug..can't remember)
That won't really be a factor unless you are using digital equipment or timers.

The .2 amp means that it will use up the AC voltage at a rate of .2 amps. This means that when you are adding up all of your grow room devices, to make sure you have the proper electric circuit and breaker, you will need to add .2 amps to the figure when you use the charger.

We have already went over the output data.

 

[petemoss]

Bedlam,
That charger only outputs 5.1 volts and the fans you mention are 24 volt DC fans. You should get an adapter rated for the same voltage as your fan. Most case fans (computer fans) are 12 volts DC. Chargers are fairly cheap -about $15. You can run a DC fan at a lower voltage but it will turn slower and you won't get the rated CFM but it will be much quieter!

 

[Stay Puft]

Just so you know:
The "-.-.-" after 5.1V in your original post indicates a DC output. (the dots represent Ground reference, the dash a DC level)
I know it is a lil Goofy instead of just putting "DC" after the voltage. I didn't invent it, just telling you how you would have known.

You might want to consider buying a quality DC power supply off of ebay or Jameco. (make sure it is new, meets your power and voltage requirements and should cost no more than $40.00 )

Wall warts (like I am imagining your PS) are not the safest devices in the world to leave plugged in 24/7.
Part of security is... Not burning your house down!
Regards,
Stay_Puft