What would happen if I attached a case fan to a car battery?

[TheRetiredSlave]

If you want a small fan on your desk to blow air towards your hands, why wouldn't you just buy a small desk fan?

 

The even make little USB-powered desk fans, so you could have one just plugged into your computer while you game. (it seems safer to just spend ~$15 on a desk fan than to jerry-rig a bunch of wires together to a car battery)

 

http://www.amazon.com/s/ref=sr_nr_p_n_feature_keywords_0?rh=n%3A1055398%2Cn%3A%211063498%2Cn%3A3206324011%2Cn%3A3737601%2Cn%3A3737631%2Cp_n_feature_keywords_browse-bin%3A4844485011%2Cp_n_feature_keywords_two_browse-bin%3A6828826011&bbn=3737631&ie=UTF8&qid=1371736414&rnid=5901093011

[sotiris.bos]

Although the volts are the same the amperage is very high and it will most probably fry anything you hook up to it. The power supply in your computer is made to draw and supply as much power as needed, the car battery always supplies the same power (peak power) when it is above 20% charged. Do not try it.

 

Edit: You would need a controller between the battery and any device you hook up, in that case it should work. Power equals voltage multiplied by current (P=V*I) and unless you do something to control the current (and thus the power supplied) you are going to destroy your fans.

[Chevaishr]

i'll tell you what will happen ... it'll spin but it will spin the kentucky way, aka maximum rpm 

[FireFox]

My question is will the fans take the amps and burn the PCB or will it draw what it needs or run in normal operations. :)

 

I'm no electrical expert but I still think you'll burn it out, I'm sure I've seen a video on youtube with someone doing this, the fan didn't last long.

[sotiris.bos]

You could do something like this: 

[craig92]

I want to run a couple of case fans to a car battery. (It's the car battery for a Honda Civic to be more specific)

Is this possible?

 

I use these spare case fans to blow air towards my hands when I'm gaming. They are currently attached to a step down transformer that allows me to get the power from the wall outlet. Now I was thinking since the voltage of my car battery is 12 volts and I'm almost up for replacement can I use that to power the case fan in case of power outage so it can blow air towards me and keep me cool? :))) 

 

Has anyone else done this? 

Is there a better battery based solution? Hopefully one I can use for at least 1 week without recharging? 

I have about 30 USD to spare and I'm opting for this rather than buying an actual rechargeable fan cause I like building stuff and those things a quite bulky and often include lights or a radio which I don't really like. 

 

This will not work as the amps in a battery will kill the fan instanly

[random_australian]

but putting 1.5 volts in series does not make 12 volts. Amperage increases but not the voltage. :)

 

Yes it does mate here is some light reading for you. :)

 

Connecting in Series 

When connecting your batteries in Series you are doubling the voltage while maintaining the same capacity rating (amp hours). This might be used in a scooter, Power Wheels kids vehicle, or other applications. Just use a jumper wire between the negative of the first battery and the positive of the second battery. Run your negative wire off of the open connector from the first battery and your positive off of the open connector on your second battery. 

 

http://www.zbattery.com/Connecting-Batteries-in-Series-or-Parallel

 

But if you insist on using a car battery please either buy or make a battery box to keep you and the battery safe. Also make sure you insulate your connections. :)

 

My question is will the fans take the amps and burn the PCB or will it draw what it needs or run in normal operations. :)

The fans should only draw as many amps as they need. :)

[likegirls4]

The fan won't burn and the battery will not explode. The fan can handle 12 volts just fine because its rated for 12V. If it will get a slightly higher voltage like 15V, it will run a bit faster and will probably burn the fan after a while.

Also the fan will not draw to much amps causing the battery to get short ciruited. It will just draw the amps it needs. This means that the battery will power the fan for much longer time than it would for the starter engine in a car.

And don't be scared about the fact that a car battery can draw a couple of hundered volts. The current that can be drawn from the powernet in a house in Belgium is 40 amps. This doesn't mean that when you plug something in, it will always draw 40A. Thats just the maximum current that the powernet of a house can take before burning the wires.

So yes you can power a computerfan with a car battery safely, as long as the voltage of the battery is the same as the voltage the fan is rated for.

[Chevaishr]

Can you explain why?

the fan will not fry. the amount of current (amps)that flows to the fan is determined by the internal resistance of the fan. the fan would have a very high resistance so as long as the source is 12v only a fixed amount of current will flow to the fan REGARDLESS OF THE SOURCE.

but putting 1.5 volts in series does not make 12 volts. Amperage increases but not the voltage. :)

1.5+1.5+1.5+1.5+1.5+1.5+1.5+1.5=12v http://www.zbattery.com/Connecting-Batteries-in-Series-or-Parallel

My question is will the fans take the amps and burn the PCB or will it draw what it needs or run in normal operations. :)

it will only draw what is determined by the fan's internal resistance. the only way to burn the fan would be to hit it with very high voltages as an increase in voltage would allow for an increase in current flow at a given resistance.

Could you PLEASE! provide like a picture or video? :D

as you see hear dem cpu fans can take abise ... but in order to abuse them you need high voltage. which a car battery does not have.

Although the volts are the same the amperage is very high and it will most probably fry anything you hook up to it. The power supply is made to draw and supply as much power as needed, the car battery always supplies the same power (peak power) when it is above 20% charged. Do not try it.

Edit: You would need a controller between the battery and any device you hook up, in that case it should work. Power equals voltage multiplied by current (P=V*I) and unless you do something to control the current (and thus the power supplied) you are going to destroy your fans.

ok the capability of the battery is very high but think of it like this, current is not "pushed" it is "pulled" by what ever presents the load.that load is determined by the resistance. a high resistance means that little current will flow and thus a small load(because there is a lot of resistance to current flow ) . now with a low resistance there would be great current flow. with a cpu fan there exist a high resistance and thus as long as the supply is around 12 volts it would draw as much current that it is rated for on the back of the fan

[Eve]

It should work, most dangers with batteries come when charging them.

As long as the device you hook up has a lower Amperage than the battery can deliver you're fine.

A computer fan only draws around 0.25Amps, whilst a a car battery should be around 10 Amps. 

I guess your fan would run 40 times longer than it would at 10 Amps load?

[Ps_domingo]

If you want a small fan on your desk to blow air towards your hands, why wouldn't you just buy a small desk fan?

 

The even make little USB-powered desk fans, so you could have one just plugged into your computer while you game. (it seems safer to just spend ~$15 on a desk fan than to jerry-rig a bunch of wires together to a car battery)

 

http://www.amazon.com/s/ref=sr_nr_p_n_feature_keywords_0?rh=n%3A1055398%2Cn%3A%211063498%2Cn%3A3206324011%2Cn%3A3737601%2Cn%3A3737631%2Cp_n_feature_keywords_browse-bin%3A4844485011%2Cp_n_feature_keywords_two_browse-bin%3A6828826011&bbn=3737631&ie=UTF8&qid=1371736414&rnid=5901093011

please read carefully what I posted. :) I want to use the fans in case there is a power outage to cool me down. =)) 

[Ps_domingo]

Although the volts are the same the amperage is very high and it will most probably fry anything you hook up to it. The power supply in your computer is made to draw and supply as much power as needed, the car battery always supplies the same power (peak power) when it is above 20% charged. Do not try it.

 

Edit: You would need a controller between the battery and any device you hook up, in that case it should work. Power equals voltage multiplied by current (P=V*I) and unless you do something to control the current (and thus the power supplied) you are going to destroy your fans.

Though the car battery I will be using the used up one from my car now. :) So I'm guessing it wont be over 20% yes? :D

[Ps_domingo]

Yes it does mate here is some light reading for you. :)

 

Connecting in Series 

When connecting your batteries in Series you are doubling the voltage while maintaining the same capacity rating (amp hours). This might be used in a scooter, Power Wheels kids vehicle, or other applications. Just use a jumper wire between the negative of the first battery and the positive of the second battery. Run your negative wire off of the open connector from the first battery and your positive off of the open connector on your second battery. 

 

http://www.zbattery.com/Connecting-Batteries-in-Series-or-Parallel

 

But if you insist on using a car battery please either buy or make a battery box to keep you and the battery safe. Also make sure you insulate your connections. :)

 

The fans should only draw as many amps as they need. :)

If I use some sort of a connector where are parallel to each other in a 4x2 config will that work? :D

[TheRetiredSlave]

please read carefully what I posted. :) I want to use the fans in case there is a power outage to cool me down. =)) 

The first result from the link I posted was a battery operated fan for $13, along with several other battery operated fans on the same page..

Does your computer run without power?

[sotiris.bos]

The video of the fan above is not made using a battery. The fan is using max 20 volts and 0.7 amperes. That means 14W. An average car battery produces 500W of power. An old one around 400W. A battery is not like a computer power supply. The power supply draws power from the outlet and converts it to dc. It only draws the power it needs. A battery does not modulate its power. A battery does not draw current from an outlet but it discharges (which means it forces its max current to flow). If you connected the two poles with a copper wire your hand would burn (and so would the wire) because all the power will be put to use. When you connect a car battery to a car, sparks are produced. That is because of the big amount of power it produces. If you hook anything on the car battery with no control of the current it WILL be destroyed. Don't mess with car batteries. You are much better off with a laptop-like ac to 12v dc converter. Please, do not use the car battery.

 

 

Car batteries have tremendous current capabilities, and a short circuit can produce a huge, white-hot electric arc.  It's hot enough to melt steel and inflict severe burns, and to set the car on fire. The most significant danger is from the accumulation of hydrogen gas, which is released from the battery when it's working.  A spark from an incorrectly connected jumper or charger cable can ignite the hydrogen, which may cause an explosion.

 

 

Here is a video of a pencil burned with a car battery:

http://www.youtube.com/watch?v=zfxu0hDhFrw

[KaareKanin]

The video of the fan above is not made using a battery. The fan is using max 20 volts and 0.7 amperes. That means 14W. An average car battery produces 500W of power. An old one around 400W. A battery is not like a computer power supply. The power supply draws power from the outlet and converts it to dc. It only draws the power it needs. A battery does not modulate its power. A battery does not draw current from an outlet but it discharges (which means it forces its max current to flow). If you connected the two poles with a copper wire your hand would burn (and so would the wire) because all the power will be put to use. When you connect a car battery to a car, sparks are produced. That is because of the big amount of power it produces. If you hook anything on the car battery with no control of the current it WILL be destroyed. Don't mess with car batteries. You are much better off with a laptop-like ac to 12v dc converter. Please, do not use the car battery.

Here is a video of a pencil burned with a car battery:

Volts can be described as the force which pushes each electron trough a circuit. The chemistry within a battery can only deliver so much voltage. Granted, this number is subject to the charge level, but it won't vary that much. And then there's the difference in voltage when measured with and without any resistance. The difference between these numbers will tell you a lot about its health. Different batteries also have different classifications according to how many amps they can deliver over time, in my world these are known as radio batteries (Huge capacity, lower ability to deliver a lot of amps) and starter batteries (can deliver immense amounts of amps for starter motors etc).

But don't for one minute believe that any psu regulates the amount of amps they deliver, because that's not how it works and the PSU has no idea about how many amps it should deliver. That's entirely controlled by the voltage and the resistance in the circuit. The same goes for batteries. The major difference when it comes to amps is that batteries doesn't (didn't) have over current protection. If the current becomes to high the psu will probably shut down because of this, and can in basic therms be described as a fuse. With batteries that doesn't have this, they can potentially deliver so many amps that bad things can happen.

Be aware that very few 12V "car batteries" are at 12 volts, they are usually upwards of 14V, so a fan might be overvolted

But to reiterate, higher voltage will push higher current through. The ability of a source to deliver extreme currents doesn't mean squat unless it has the voltage to support it

[Chevaishr]

The video of the fan above is not made using a battery. The fan is using max 20 volts and 0.7 amperes. That means 14W. An average car battery produces 500W of power. An old one around 400W. A battery is not like a computer power supply. The power supply draws power from the outlet and converts it to dc. It only draws the power it needs. A battery does not modulate its power. A battery does not draw current from an outlet but it discharges (which means it forces its max current to flow). If you connected the two poles with a copper wire your hand would burn (and so would the wire) because all the power will be put to use. When you connect a car battery to a car, sparks are produced. That is because of the big amount of power it produces. If you hook anything on the car battery with no control of the current it WILL be destroyed. Don't mess with car batteries. You are much better off with a laptop-like ac to 12v dc converter. Please, do not use the car battery.

 

 

 

Here is a video of a pencil burned with a car battery:

ok so what on earth happened to v=ir ... by using this equation let us assume the fan places a 100 ohm load on whatever 12v power source the equation becomes 12=(i)(100). now solving for "i" (aka the current) we get  i=.12 amperes. now lets say our power source was a car battery and we are using the same fan then  using the norman car battery voltage (13.7) the equation now becomes 13.7=(i)(100). solving for "i" again we see the fan draws .137 amperes now from p=vi>>> (.137* 13.7) we see that a quite efficient and small fan may use 1.87 watts from a car battery. also from this i can calculate how long the fan can fun for. let us assume the battery is rated at 85ah (yup it's a big one) this mean that one can draw 85 amperes from this battery for one hour   . now this brings us to the question on how long it would supply .137 amperes for, well 85/.137=620.43 hours or just over 25 days. now for fun lets say one were to use a piece of wire as the load   and lets say that wire has a resistance of .001 ohms. the equation becomes 13.7=(i)(.001) this means that the wire would "pull" 13700 amperes or 187690 watts. now you may be wondering why cant one alter the rotation of the earth if they short a battery with a superconductor. well in the real world there exist something called internal resistance it is this internal resistance which cause a voltage drop across the poles when placed under heavy load (eg starting the car or playing music).when starting a car a lot of the internal electrical items go out and if you have the lights on they too dimm this happens because the battery cannot maintain the current flow (as it is not a perfect battery) and thus drops the voltage. the relation that is setup is such that if current must vary then the voltage must vary IF the resistance placed on the battery is constant. 

 

 

i have a car audio background which means multiple times i have connected pc fans directly to batteries to cool off amps. not only do i have my experience i have also researched deeply into the electronics field (relating to car audio). also with respect to the wattage you quoted for car batteries it is not 400w to 500 watts  it is more like 6000w to 9000w of instantaneous power one can get from a lead acid battery.

[Chevaishr]

The video of the fan above is not made using a battery. The fan is using max 20 volts and 0.7 amperes. That means 14W. An average car battery produces 500W of power. An old one around 400W. A battery is not like a computer power supply. The power supply draws power from the outlet and converts it to dc. It only draws the power it needs. A battery does not modulate its power. A battery does not draw current from an outlet but it discharges (which means it forces its max current to flow). If you connected the two poles with a copper wire your hand would burn (and so would the wire) because all the power will be put to use. When you connect a car battery to a car, sparks are produced. That is because of the big amount of power it produces. If you hook anything on the car battery with no control of the current it WILL be destroyed. Don't mess with car batteries. You are much better off with a laptop-like ac to 12v dc converter. Please, do not use the car battery.

Here is a video of a pencil burned with a car battery:

also capacitors can deliver more current than a car battery as they have even lower internal resistance than nearly anything you can easily get your hands on

[_wky]

12V, fine, not sure about the current though, car batteries can put out quite a few amps

[Chevaishr]

Volts can be described as the force which pushes each electron trough a circuit. The chemistry within a battery can only deliver so much voltage. Granted, this number is subject to the charge level, but it won't vary that much. And then there's the difference in voltage when measured with and without any resistance. The difference between these numbers will tell you a lot about its health. Different batteries also have different classifications according to how many amps they can deliver over time, in my world these are known as radio batteries (Huge capacity, lower ability to deliver a lot of amps) and starter batteries (can deliver immense amounts of amps for starter motors etc).

But don't for one minute believe that any psu regulates the amount of amps they deliver, because that's not how it works and the PSU has no idea about how many amps it should deliver. That's entirely controlled by the voltage and the resistance in the circuit. The same goes for batteries. The major difference when it comes to amps is that batteries doesn't (didn't) have over current protection. If the current becomes to high the psu will probably shut down because of this, and can in basic therms be described as a fuse. With batteries that doesn't have this, they can potentially deliver so many amps that bad things can happen.

Be aware that very few 12V "car batteries" are at 12 volts, they are usually upwards of 14V, so a fan might be overvolted

But to reiterate, higher voltage will push higher current through. The ability of a source to deliver extreme currents doesn't mean squat unless it has the voltage to support it

you are quite right sir however i have yet to burn out pc fans at 14 volts so i think the op should be safe though the longest i have ever run them was about a half hour 

[_wky]

also capacitors can deliver more current than a car battery as they have even lower internal resistance than nearly anything you can easily get your hands on

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