Spark damage...and prevention

A couple of weeks ago I was prevented from flying "one last time" because my 4mm bullet connectors sparked so much that they damaged the end of the connector on the ESC enough to stop me connecting another battery. I replaced all my connectors with shiny new ones and went flying yesterday. The first battery sparked and damaged the connector again, preventing any flights with that model. I need a way to prevent that spark...

I've added a 2mm female connector to the negative lead of my ESC. I've then made a harness that has a 2mm male connector on one end, a crocodile clip on the other, and a resistor inbetween. The resistor is much bigger than needed, but it is one I had. I'm sure that any 1/4 watt resistor of about 10 ohms will do the job. I'm sure I've got a load of small resistors somewhere, but could not find them.

To make the connection without a spark you need to connect the positive battery lead to your ESC first. Then connect the harness with the 2mm plug and the other end to the 4mm male on the battery. Now slide the male into the ESC female before removing the crocodile clip. No more sparks and long life to my connectors.

And here's what the damaged connectors look like. Top is from a couple of weeks ago. Middle is from yesterday...just one spark did this. Bottom is what they should look like.

Hi Mike, Sounds like a DIY version of the jeti anti spark connectors, it seems a little odd that it's suddenly become an issue when you've been putting in hundreds of flights on the Blue Angel without issue. I'm just wondering if you're using a new batch of connectors and the metals not as good?

Chris001 wrote: I'm just wondering if you're using a new batch of connectors and the metals not as good?

My thoughts too! I have never had an issue as Mike has described or in other words had to replace connectors because of burns. Maybe have a multimeter set for DC current and monitor initial current as ESC loads up. I would've thought no more than an amp or two. Only a guess as I have not run this test myself yet or needed to.

Footnote. Virtually all my connectors in what ever type are all Hobbykings'

Hobbyking have a lower cost solution to Jeti also available from bang good in China
www.hobbyking.co.uk/hobbyking/store/__61...tor_2pairs_bag_.html

Interesting to read of Mike's experience it does seem strange that the problem has just arisen.
I am using 3 & 4 cell LiPo's with 4 mm bullets , the "little" spark not being strong enough to do any damage.
I'm assuming Mike is 6 cells, so how do guys with 8,10 & 12 cell setups cope ?
Colin. A

I expect the arc comes from the inrush current into the ESC Input capacitors. Maybe Mikes speed controllers have higher value/quality caps fitted.
His resistor pre-charges the caps to reduce the inrush current when connecting the power proper.

I've been using 2 different10s setups in my 2m Extra for 4 years and Vanquish for 3, big juicy spark every time I connect, but never needed to change a connector. Makes me wonder if you have an issue with your esc Mike?

JonTappin wrote: Makes me wonder if you have an issue with your esc Mike?

I appreciate that it is my ESC. However, the fact that anti-spark connectors are made indicates that I am not the only one experiencing this issue. The fix is simple and completely removes the spark.

PhilF51 wrote: My thoughts too! I have never had an issue as Mike has described or in other words had to replace connectors because of burns. Maybe have a multimeter set for DC current and monitor initial current as ESC loads up. I would've thought no more than an amp or two.

You'd need a 'scope to measure the current...it is such a short spike and a multimeter would not be able to detect if fully. My guess is that we're talking several hundred amps for a millisecond or so