Ac powered laptop cooler - need help

[andynerd]

I have 3 computer fans and now with my laptop overheating I thought I would use them to keep my computer cool. I have taken an old flat bed scanner gutted it and used it as a base. I have everything mounted I just need to make up a circuit. I have a power supply from some electronic gadget that has long since died but the power supply still works. Being me I like to make use of everything so I need a circuit to convert 9v 1A power into 12VDC .19 .20 and .25 A ( The fans are different sizes). Or I could just generalize the ampers at .20. Anyway so being a 15 year old know nothing I don't know really how to do this. So if anyone has an idea it would be much appreciated!

 

[Andy1845c]

I would just get a different power supply. One that puts out 12 volts and atleast 1 amp. You could possibly use a power supply from a desktop computer if it is not too big in physical size.

Stepping up a small power supply from 9 volts to 12 volts in going to be more hassle then it is worth, plus, your 9 volt supply will not be able to put out 1 amp at 12 volts. I doubt it would even be able to run all three fans.

 

[Sceadwian]

I second what Andy says, since you're not sure what you're doing, find a 12V supply. Try thrift stores if you can't find one you can use. 12V supplies are common with small audio power speakers and many other devices. 1amp will give you over head, as the three fans you mentioned will draw a about .65amps.

 

[andynerd]

How about a 12V 1250mA scanner powersupply? It does sound a lot simpler.

 

[arunb]

yes that will do, connect the fans in parallel to each other, as shown in the attachment.
Also ensure the polarities are correct, + to + and - to -.
Red colour wire is usually +, and black -.

Wrong polarities will not damage the fan.

hope this is helpful

thanks
aa

 

[andynerd]

Thanks I didn't know the fans could take that much without damage

 

[HiTech]

Just use a 12vDC wall wart rated 12v @ 800ma or so. Simple, cheap and effective. You don't need a well regulated supply for a couple of fans! Check with a local computer service shop or similar electronic service place. Often they have them lying about by the boxes!

 

[Sceadwian]

Andy, just because the power supply is rated for 1250ma's doesn't mean it HAS to supply that much, only that it can. If a 12V 100ma device is hooked up to a 12v 5000ma power supply it's still only gonna draw 100ma's. I mean you can hook a 12V fan up to a car battery and it'll run just fine even though a car starter can still draw a few hundred amps off the same battery.

 

[andynerd]

To HiTech ya I would but being a lazy 15 year old I only have about ten bucks on me lol! If only i didn't hate change so much. And to you Sceadwian thanks for that information! You learn something new every day !!

 

[Noggin]

I think I would address the cause of the laptop overheating rather than trying to cool it off.

 

[Torben]

I think I would address the cause of the laptop overheating rather than trying to cool it off.

That's not a bad point. Why is the thing overheating? Overclocked? Or is it just clogged with dust? A good layer of dust inside is a surprisingly good insulator--opening up the machine and blowing it out with a can of compressed air can help. Just don't blow the air directly on the fans more than you need to; you could potentially add wear on the fans by spinning them faster than they're made for.

How old is this laptop? When was it last cleaned? Has it always had this problem?


Torben

 

[andynerd]

Oh it is overheating because when I installed an old windows xp sp1 CD to my laptop trying to convert it from vista to XP it installed as an ACPI PC instead of a Uniprocessor PC so the fan sometimes doesn't work and standby never recovers. Better option then buting a $200 dollar windows CD... Like I said I am lazy xD!

 

[andynerd]

That's not a bad point. Why is the thing overheating? Overclocked? Or is it just clogged with dust? A good layer of dust inside is a surprisingly good insulator--opening up the machine and blowing it out with a can of compressed air can help. Just don't blow the air directly on the fans more than you need to; you could potentially add wear on the fans by spinning them faster than they're made for.

How old is this laptop? When was it last cleaned? Has it always had this problem?


Torben

It is one year old roughly, was on lay away, the source started the warrenty on the day it went on lay away instead of the day I received it! It has been cleaned, but have the worst luck with everything, I am not going to even think of opening it up. I just stick the end of a vacume up to all areas even the fans vent. That wasn't the cause of the fan not working the fan never spun O-o it just sat there when I put the vacume up to it. Last but not leased the laptop was $500 around the time I bought it and it is an acer I own two acer laptops and they are both cracked at the lid hinge and the power cord is defunked at times. And no it is not overclocked.

 

[arunb]

have you made the cooler ??