Traxxas sells a fan for the Veleneon VXL-3s esc for for example the slash 4x4. But the price of those can be as high as €30,-. So I decided to make my own for just €1,50.
Step 1: Collect the Parts
You can buy them for very cheap from AliExpress.
We will be driving the 5v fan on 6v but it should be able to handle it and it will make it a little more powerfull aswell.
We also need some clear nail polish to waterproof the fan.
Step 2: The Tools You Will Need
The most important tool we are going to use is a 3D printer to print the plastic bit that holds the fan on top of the ESC. We also need to crimp the jst connector to the wire of the fan. I just used needle-nose pliers for this but if you have a dedicated crimping tool you can ofcourse use that instead.
Step 3: Printing Out the Files
First we will print out the parts. You can find my designs on Thingiverse. To get it right the first time you have to know some important print settings. You have to enable brim (to hold on small support structures) and support (for the jst connector holder on the side) in your slicer.
While this is printing we can move on and start waterproofing the fan.
Step 4: Waterproofing the Fan
We need to waterproof the fan because it will be used in a waterproof car. We will do that by applying some clear nailpolish to the small pcb inside the fan. This is the most difficult proces of this project so if you won't use it in wet conditions feel free to skip this step.
To get to the pcb the fan blade will need to come off. If you peel off the sticker on the back of the fan you will find a small nylon washer. For the fan blade to come off this will need to be removed. Do not lose it or your fan will be useless. Once that is done we can carefuly push on the axel to pop out the fan blade. Now the pcb is visible. We will apply some nailpolish on the back of the pcb without getting it on the windings. I do not have a method of getting the pcb off in one piece so this is a tedious process. I find it easiest to just get under it with the brush. If you accedentely get some on the windings it is no big deal. But you should wipe it off to avoid the fan jamming.
Once you are done applying the nail polish you need to let it dry for a bit. After it has dried (when it stops smelling) you can chose to put on a second coat or to already test it. I would recomend a second coat but that is up to you.
Step 5: Testing the Fan
Assuming the fan worked before the waterproofing we can now test if we did a good job.
Find something to power on the fan, for example 3 AA batterys in series which will make 4.5 volts which is fine. But I used a small 1s lipo. We also need a small container and some water. Now power on the fan and submerge it into the water. It should keep running. To really test it shake it a bit to get all the air out. If it stops running it will probably turn back on when it has dried again but if this happens you should quickly disconnect the power from it. Then dry it off, test if it still works and re apply the nailpolish.
If it is indeed waterproof we can move on to the next step.
Step 6: Adding a Jst Connector
The velineon VXL-3s esc has a dedicated fan connector in the form of a female jst connector. So to power the fan we will need to add a male jst connector to the fan.
The jst holder on the 3D printed design is just next to the fan so we only need a very short piece of wire coming out of the fan, so cut it of at about 4cm. Next we will strip off about 2mm of the insulation and crimp on the jst connector bits by first crimping the small tabs to the metal part of the wire and after that crimping the larger tabs the insulation of the wire. Once that is done we can insert the metal bits in to the correct hole so the red wire of the fan connects to the red wire of the ESC and the same goes for the black wires.
Now the fan is complete and we can start assembling the whole thing.
Step 7: Assembling Everything
By now the 3D printer should be finished and we can finish the parts. Take off the brim and the little towers that support the overhangs and remove the support from the jst holder. To make it nice I like to sand the top of the fan guard and the top of the main piece.
Once all the parts look nice you can now insert the fan into the main piece so that the wire comes out of the hole and the fan faces up. Insert the jst connector in the holder and put on the fan guard by inserting the little pins into the holes of the fan. It should be a snug fit but you could add a little glue.
That was it, it is complete. Now we can test it :)
Step 8: Installing It on the ESC
This is pretty straight forward but the small retainer legs tend to snap off when to much force is applied so put it on carefully and it should be fine. The little legs should grab onto the heatsink when fully pushed down. I found the connection made by the retainer legs so strong that I can lift my entire slash 4x4 from it! Finally connect the jst connector from the esc to the fan and the installation is complete.
When you turn on the ESC by pressing the button the fan should start turning. If it doesn't, check te connections and make sure the fan is still working.
Step 9: Wrapping It Up
You can now test drive it for the first time, enjoy!
I have noticed a small reduction in airflow when the fan guard is used but it does help against grass and twigs touching the blades.
Thank you for reading this instructable, if you have any questions or possible improvements leave them in the comments.