Anti Spark Circuit
last updated 10-30-2009
This is to remove the spark that occurs when connecting the battery to the ESC. The spark occurs because of the capacitors in the ESC. A capacitor is like a battery in that is stores energy but unlike a modern battery the capacitor instantly charges up. Just as the metal contacts of the connectors touch a high current of electrons causes a small carbon spot. Eventually the carbon buildup can be large enough to cause problems. The picture on the right shows the arc spots.
In the video you can hear the spark as the battery makes contact. Just after this is the same thing but with the lights off and the camcorder in night mode. You can visually see the flashes from the spark. Then after this is the anti-spark circuit being used.
|There are a couple of things to note in
this picture. First is that I have a female connector
plugged into the male. This is a tip you should use
anytime you are soldering these type of connectors.
Before I found out about this tip I had some plugs that
were difficult to plug in and so tight to unplug that I
was trying to figure out some mod to solve this. The
reason for all the trouble turned out to be due to the
metal plates moving out of place while they were hot from
soldering the wires. By placing another connector on the
one you solder, this holds the plates in place and also
acts as a heat sink.
The other thing to note in the picture is that I am placing the anti-spark circuit on the negative side. You can put it on the positive side but the way I connect the plugs has the positive side contact first. As you can see in the video I made, I start with the two plugs angled about 45 degrees to each other. I let the two positives touch then tilt the plugs so the negatives contact and then push the plugs together. So for the anti-spark circuit I connect it first then to complete the circuit path I touch the positive contacts of the main plug. You can see this in the video posted above.
In the picture you do not see the heat shrink tubing on the negative wire but it is there. I slide it down on the next step. The small wire I used is from a servo wire. 20 to 22 gauge wire is fine for this circuit.
|In this picture you see I slide the heat shrink tubing over the small wire and onto the solder joint. Then I put a smaller heat shrink tube on the small wire. Next I soldered a 39ohm 1W resistor to the small wire.|
|Here you see the small 2mm bullet connector is soldered to the other side of the resistor.|
|This shows the female bullet connector that will be installed on the battery side.|
|Make sure the heat shrink tubing is cut so that it does not get in the way of the female plug.|
|This is the battery side. The small wire is again servo wire. You do not use a resistor on this side. Just the wire and the 2mm bullet connector. BTW: the positive wire on the connector does have heat shrink, it is just clear.|
|This is the setup for my 6S battery pack. The ESC is on the right and the battery on the left.|
|This is for my two 3S packs.|