Finding Fan Voltage

I am currently planning on modding my overheating laptop with some new internal fans. In order to do this right, I need to know the voltage that my current fan operates off of.

Before I get out my voltage probes and try to get a reading while the thing is taken apart and running (which strikes me as stupid and dangerous), I want to see if there's a way to find this through software, or even find the voltage through somebody knowledgeable that is on these forums.

So, my laptop is a Dell XPS M1210. Does anybody know what fan voltage that model uses, or software that can tell this to me? (speedfan oddly does not)

 

from my experience it is going to be 5V.

also if you take it apart it should be written on the fan.
good luck


Edit: when you put some new internal fans, consider using 6mm thick ones. Also look for 6mm thick blower fans.
If you use 5V fans you can attach then directly to usb power (just use the solder points of the usb port on the motherboard).

the usb port also provides 5V so it's a good match.

 

Actually, they are beginning to manufacture 4mm deep fans. I plan on using two of these:

http://www.asianproducts.com/product_9/15x15x4mm-DC-Atomic_P11973423093257421.htm

There's a perfect spot for them on the underside of my overheating graphics chip, where the WWAN card is supposed to go.

 

Yep, should be 5V.
Are you sure you're going to have enough to work with in the laptop? Might be worthwhile just to clean out the dust instead of trying to fit a new fan in there.

 

Every laptop fan I have ever come across was a 5V fan

If you want, you can power the fan off of the USB hub, which is also 5V.
You can also choose to short the fan controller, which will force the fan to run at full 5V
Or
You can make a Circuit with a microcontroller, so that you can make the fan speed what ever you want it to be. This can be controlled/programmed through the serial or parallel bus

K-TRON

 

I may end up running off of the USB hub since that's closer than the fan that's already in there. A microcontroller would be clever, but a bit overkill as a trim pot in series would do the same thing.

The laptop isn't dusty. It's poorly designed. That's why Dell doesn't make 12" XPS laptops anymore

 

I am wondering what the typical current consumption of the laptop fan is? If it is more than 0.5A, single USB port may not suffice.


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no way near 0.5A.
It's more like 0.06A.

you could maybe run multiple fans from one usb port.

 

@grahf121, thanks for telling me about 4mm deep fans

I'm actually planning on doing the same thing.

 

If your looking to replace the fan, I suggest getting a DELTA, SUNON, or NMB blower
Tubeaxial fans are not the right type of fans.

K-TRON

 

I am wondering if I can use a 12V fan if I connect it to 2 usb ports.
I know it will only give it 10V but it should be enough right?

So I plan on connecting the + terminal of one usb port to the + terminal of the other usb port. The - terminal to the other - terminal, then connecting a 12V fan to that setup.

I would just like someone to confirm that I have this right. I mean this wont short anything out will it?

 

I don't think that will work. Are you sure they're separate rails?
If you must use a 12V fan you can use a TI ptn04050c module which will boost the voltage up. It's reasonably small.

 

I am 99% sure that you will short the power lines of the USB ports and burn out some of the chips. Never ever try that unless you are 110% sure that USB ports have different power rails.

Additionally, if you connecet + to + and - to -, you will end up with a parallel connection which will deliver you 5V and 1 Amps (0.5A x 2). If you want to get a serial connection, you need to connect one of the + to the other's - and use the remaining + and - to have 10V, 0.5A (assuming that those power lines were fed by different rails).


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Definitely cannot just use two USB ports to double the voltage. At least not if you want a functional laptop. Even if they were one different power rails (which they won't be) chances are virtually guaranteed they would still share a common ground. Any design worth its salt would be designed that way.

You'd want to invest in a boost circuit to handle this.

 

ok thanks, I knew it wasn't a great idea.

 

K-TRON, why are tubeaxial fans bad for this application?

I am using 2 of these fans for my mod:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=563-1106-ND

These are the equivalent blowers for this purpose:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=UB3H3-100-ND

The blowers have a air flow of .011 CFM, as opposed to .424 CFM on the tubaxial fans. The key will be ensuring sufficient breathing room on both sides of the fans. But I'm stumped on how a pair blowers could possibly be superior to a pair of fans. The difference in air flow is over an order of magnitude.

I've also changed my mind about pulling off of the USB hub because its power leads are not easily accessible. I'd have to cut into the port to get to the leads, which is a lot harder than just pulling off of the fan lines that are already there. Using the USB hub would also require a voltage divider, as the fans run on 3.3V, which would not be an efficient way of doing it.

Once the fans arrive, I am going to document my mod and post it here. I have a few other tricks up my sleeve that I'll share then too.

 

first off you need to look at the airflow through your laptop
Almost all laptops use blowers, because they pull air through the bottom and output the air flow 90 degrees from the intake. That would allow the air to flow right into the fins of the heatsink

With a standard tubeaxial fan, the air flow is a straight line. If you try mounting a standard tuebaxial fan to replace a blower, you will find that despite the higher cfm, it will have less of a cooling power. You greatly decrease the efficiency of small tubeaxial fans, by having restrictions in flow such as a 90 degree bend.
With a blower, there is no decrease in performance, and usually blowers carry a higher pressure behind the air volume, which keeps the air moving through the heatsink

Those fans you found are no good, you will want around 4-8cfm for your cooling needs. half a cfm will do nothing

You should look for laptop blowers on ebay or in the marketplace. X2P might have one still in his vostro parts sale. They are designed for laptop use, the ones you found, not so much

K-TRON

 

I see your point, however I am not replacing anything. I'm implementing 2 additional fans directly underneath my GPU, where there was an empty space before. I'm not sure if I mentioned that. I'll be posting pics on what happens later this week. Then maybe it will be more clear what I'm attempting.

 

Oh, okay,
so youre trying to add an additional fan in the empty space

Any ideas how much space you have?

You can have fan manufacturers custom build fans for you.

However you may want to try Sunon's Micro maglev fans, they are the smallest I have ever seen. I believe they go down to 10mm in diameter

K-TRON

 

It took me tons of research to find the fan that I did. I've never had so much trouble trying to find and purchase anything in my life.

Most of the fans that I found were only being distributed in large quantities. I also almost spent $80 on a pair of 15x15x4mm fans from europe, before I searched digi-key's website.

The fan I bought is manufactured by copal, and is 16x16x4mm. I did see some fans that were smaller, but I believe that the CFS a fan can move goes up exponentially with diameter. I can fit two of these things into the space I have.

 

Have you tried searching Mouser?

http://www.mouser.com/Search/Refine.aspx?N=1634435

Seriously, check Delta, NMB, Sunon, Y.S. Tech, they have plenty of them.

I have a 20mm x 20mm x 10mm Y.S in one of my Mitac laptops and the fan is actually quite powerful

K-TRON