Computer fan

[Sealiesa]

Hi, I want to make a vent for my boat with a couple of fans from a desktop computer to blow the hot air out of the cabin, how should i connect them up as they would be run from a car battery 12v. do I need to reduce the power in any way or can i wire them straight up?

[PhilB]

Hi, PC fans are 12v rated and will connect direct to a 12v battery but as a boat (20ft Matilda lifting keel 4 berth yatcht) owner myself I would advise you look more towards a small specialist marine extracter fan as PC bushless fans dont fair well in damp situations and realy dont like salt residue in the air after looking at my boat laptop cooling fan, you can buy a 12v boat fan that is similar to the small ones used on the dashboards of trucks and cars but meant for boats with sealed bearings and watertight electronics and if placed on a small shelf faceing an open port or vent will drive out the warm cabin air or blow in fresh colder air if turned the other way, alternatively if you have an old cheap holiday hairdryer the motor and fan units in them are quite often generic low voltage units with the 240v bridge rectifier diode setup on the input pins on the rear of the motor, bypass these diodes and 12v will drive this fan and motor unit slower than the norm but quiet as they are normally rated up to 30v (please check input voltage before testing!) and these little things can move a lot of air and handle damp air due to the nature of the useage. There is also the bonus that you only need a vent of a few round inches cut into your cabin and the motor fan unit fits nicely into a few inches of white plasic waste pipe!
I have one already stripped out for another use if you would like detailed photos how it looks and how to wire it up.
regards
Phil