Some of the less expensive battery chargers you buy tend to get hot when in use. The main culprits are the ones that can use AC and DC power. Many have found that if you use a fan on them, it not only helps keep them cool, but extends their life.

I've seen everything from desk fans to custom made used, but one of the easiest and slickest ways to do it is using a computer CPU fan.

http://www.hobbytalk.com/images/articles/cfana1.jpgComputer CPU fans can be bought at almost any store that sells computer supplies. They are small (approx. 2") diameter pancake fans that have many uses in RC. I'll show you an easy way to mount them on your charger to keep it cool and help make it last longer.

In my example I installed the fan into an Apex Alpha charger. This is an AC/DC charger that is known to get hot enough to burn you when used with AC power. It's a prime example of a charger that can benefit from the installation of a fan. This same method can be used on almost any charger to get the same results.

You will first need to pull off the cover of your charger to find the best place to fit the fan. In the Apex charger there is not enough room to fit the fan inside the case, so we elected for an external installation. The efficiency of the fan is not affected by either installation method, it's just a neater package if it can be mounted inside the case.

http://www.hobbytalk.com/images/articles/cfanb1.jpgYou will need to measure the diameter of the fan you get and head to the hardware store to pick up a holesaw that is the same size. You don't have to use a holesaw, but it sure makes it easier to get the round hole that is the right size.

If you don't have a hole saw available, you can drill a hole in the case and use a Dremel tool to enlarge the hole to the proper size. Of course this will take longer to do and you may not get as neat a hole as with a holesaw, but if you mounting the fan on the outside of the case, it will cover the hole you are making.

http://www.hobbytalk.com/images/articles/cfanb2.jpgRemove the fan from the heatsink if it is mounted to one. Place the fan over the hole you just cut and mark the placement of the fan mounting holes. Drill these holes as needed and then mount the fan to the case.

You now need to find a place in the charger to hook up the fan power leads to a 12V DC source. If you are not comfortable working with electricity, then find someone who can do this for you. In AC powered chargers there is 110 volts in the charger and getting shocked by it can cause injury or death. Always be very careful when working inside a charger when power is supplied to it, even when it is powered by DC.

http://www.hobbytalk.com/images/articles/cfanc1.jpgIn the Apex I found that the AC/DC converter was a great place to tap into for the 12V DC needed. This device is hooked to the the output of the AC transformer and all AC/DC chargers should have something like this in them.

Just solder the leads from the fan as needed. Make sure the fan will blow "in" on the components to get the most out of the installation.

Now just bolt up the fan to the case and reassemble the charger. You can buy a fan guard if needed. It is not necessary, but is nice to have to keep things (like your fingers) from touching the fan blades. The fan is not powerful enough to hurt you, but it sure will make you jump if you touch it...

http://www.hobbytalk.com/images/articles/cfanc2.jpgHow well does it work? The Apex Alpha used to get hot enough when using AC that it would be uncomfortable to the touch. Now it stays cool enough that is is barely warm. It is not only safer but should greatly extend the life of the charger.

Parts Required:
CPU Fan: Radio Shack #273-246
Fan Guard: Radio Shack #900-2524
Soldering Iron
Misc. Bolts & Nuts to mount fan
Hole Saw (optional)