bridging volt lines ?

[MilkMoney]

Is it safe to bridge the 5V and 12V lines together on external hard drive power adapters??
Like how they do pc psu's so i can get 5V+12V/2 fans = 8.5V each?

https://www.icmag.com/ic/picture.php?albumid=7678&pictureid=133607

 

[MilkMoney]

these power adapters

these power adapters

 

[stonedwarrior]

no.

 

[OldGuyInOregon]

Is it safe to bridge the 5V and 12V lines together on external hard drive power adapters??
Like how they do pc psu's so i can get 5V+12V/2 fans = 8.5V each?

It is possible but not recommended. I'd simply parallel the fans and let them deal with 12v. If the fans only last a year who cares. If 12v is too much for the fans, or if they are expensive I'd add a smallish one watt resistor in series with each fan.

 

[r2k]

No. Bad idea. Sparks, smoke, fire, 911 call.

5+12/2 equals 11, not 8.5. Not sure what you are trying to do here and how you plan to get there.

You could run two fans in series to get them both to run half speed (assuming both fans have the same current rating).

-r2k

 

[MilkMoney]

equals 11?
Nah was just wanting to cut noise down a bit and didn't really need the full wind that 12v was putting out but 6V isnt quite enough wind lol They're not same amps so series no good im just running at 12v it will do replacing thems no problem just cheap recyceled from old pcs
thanks guys no fires started here

 

[r2k]

I think you could run two computer fans in series to get what you want. Both would run at about half the rate (assuming they are matched fans) and the wind noise should be cut by something like one fourth.


-r2k