Scrap Computer Case Fans Reused for Hot Sunny Day

It got very hot one day and we are all feeling the effects from over heating. I thought I go to the supermarket to purchase a couple of desk fans. Problem is, I was too slow in reacting and every where was sold out and was so typical me. This is when I had a idea, I wondered all the disused PC case fans in my cupboard, would it be any good with this problem. One fan on its own would not help much, but what if I wired the whole lot together?

The odd thing, it worked incredible well building a wall of PC Case fans. So I made one for each room from all the scrap components from a past work.

What you need!

Soldering iron,solder, wire cutters, Heat shrink tubing. Case Fans, i used scrap from pentuim 4 days or can buy new. Laptop power supply at 12volt at least 3amp, Cable ties & some form of fan base, Chicken wire or even fan guards, rubber edging of any kind.

I must have built at least six different versions; one for desktop; two for bedrooms, two for my workshop; using reclaimed materials.

Step 1: Calculating DIrect Current Needed.

Counting up all the 12volt fans, how much amps they use together is critical for number of reasons.
Using a power supply that does not produce the amp rating needed for the fans requirements, is only result in the overload, overheating, burn out of the power supply as cannot keep up demand, it just dangerous as well. . PC fans have a advantage of coping with viable amp,volt power input, making it go faster or slower depending on the power input, but will have a minimum working amp/volt rating to start spinning. Like running LED lights brighter or dimmer, same principle as LED have minimum working voltage as well.

It better to be slightly over than under with laptop power supply amp supply, matching the 12v fan input.
A good quality laptop supply has overload protection built in, that why like using it and smaller chargers not so good in dealing with overheating.

I used a Acer 4552 12v laptop supply as had a very close matching amp output to the set of fans I assembled, plus I reused a power jack from a disused laptop. I did not have to alter the power cable in reducing short circuits.

You have add or remove fans depending on the power supply you already got or want to buy?

I avoided using batteries of any kind due to the huge power watt draw, which can cause batteries to rapidly overheat from high demand of current.

Step 2: Wiring.

The next thing to plan is lay out the fans in a shape you want together and working out where the wiring is going to run to one central connection at the base or side. So there might be a situation, might have to extended some case fans wires to reach.

Some case fans come with 12v molex connectors, in some ways is perfect as you can connect multiples together without doing any soldering in the base of the fan. See picture 1A. If you are using pc fans designed to plug into the mother board, then need cut the end off and extended the Red live & Black ground wires to a central point. Do we need decouple the fans from each other and I found it not needed as not run into any problems as no integrated circuits are involved decoupling usual needed for.

Step 3: Cable Ties Together.

Simple feed cables ties through each adjacent fan corner holes and pulling together the top and the side fans.
The cables run on the inside of the connecting fans to the base.
You most like have to feed two cable ties through the same hole, so it pays not to use too large cable ties.
Also can use any wire fan guards as well connected in the same way.
It pays if people like sticking fingers into the fan as will hurt and break the fan completely.

Also at the same time add finger guards out of cheap pc protection guards or fine even chicken wir, if someone is going to stick their fingers into the fan in a home environment.

Step 4: The Base.

When finished the main unit of your fan and feeding all the wiring into the base. Soldering all the Red live wires and Black ground wires together or using moles connectors, wiring it to the input laptop jack rescued from discussed laptop. I just a matter checking for short circuits and your polarity is right.
You can use cable ties to connect to the base or use cheap nuts and bolt kit I got from a children’s toy. Fuse is a bonus for extra protection.

Time taken, depending on how many fans you are using, as all I know it kept everybody happy for the day I spent wiring the fans together what was in my electronics bin.

Step 5: Or Build From New.

If you don't have access to disused computer spares. Can you always build from new from buying job lots from online online auction sites, tend to be allot cheaper. Examples of a large Red desk fan and soldiering extraction desk fan with attached carbon filter.