Spark reduction and "contact bounce"

[npomeroy]

I've assembled a cable with a 1 Ohm length of resistance wire and am considering using it to to suppress the spark on my CC Edge 60HV ESC, just by temporarily connecting via the resistance cable to load the capacitors, then disconnecting and connecting the batteries directly. Is there a downside to this, rather than using a wired-in resistance so there is no interruption of the circuit? It seems to me there must often be "contact bounce" when plugging lipos in to an ESC, i.e. brief on/off events while the connection is secured. So a brief interruption between the resistance connection and the resistance removed should do no damage?

Nelson

[CharlieK]

A better way might be to add a parallel cable that has resistance built in.
you connect it first, wait a few seconds, and then connect the main connectors. Some sparking is still likely to occur with HV batteries, although it will be much reduced.

[npomeroy]

Originally Posted by CharlieK

A better way might be to add a parallel cable that has resistance built in.
you connect it first, wait a few seconds, and then connect the main connectors. Some sparking is still likely to occur with HV batteries, although it will be much reduced.

Thanks Charlie. But I am trying to avoid changing my existing cables, so hence I am asking the question. It can't be unprecedented that a person makes a connection and then breaks it again before completing it (especially if spooked by the spark). I'm trying to be extra careful by asking if this on/off/on connection is a problem or not.

[nightflyr]

I use something close to your set up..
I have a resistor wired on a momentary switch to the main batteries.
I flip the switch to charge up the ESC, then connect the main packs.
Then switch off the resistor.

[npomeroy]

Originally Posted by nightflyr

I use something close to your set up..
I have a resistor wired on a momentary switch to the main batteries.
I flip the switch to charge up the ESC, then connect the main packs.
Then switch off the resistor.

If you switch the resistor off after you connect the main batteries to the ESC , then this is not my situation.
My point is - I don't want to cut/solder into my battery or ESC cables to create a fixed parallel line. I instead want to create a temporary series connection (that incudes the resistance) between one battery cable and ESC that I remove to make the full connection. I'm using silver bullet connectors it's easier than dual connectors like Deans etc. If I'm careful I might be able to connect the resistance cable to the male bullet with a narrow alligator clip, and with some sort of flat probe connect the other end to the female bullet, and then make the male/female connection without losing the resistance connection.
But I come back to the question: Does it matter if there is an brief interruption to the connection procedure?

[nightflyr]

I understand what your trying to accomplish.. though the thought of probing a battery lead seems a bit dodgy.

Might consider a purpose built anti spark connector ..




As to your specific question...
After the caps are charged, they will retain voltage for a short period of time.
If you wait too long, and the caps discharge before you attach your main flight pack(s) you will get a spark.
Will it be harmful to the ESC, I doubt it, due to the fact the ESC was originally designed to have this happen.

[npomeroy]

OK thanks for the input nightflyer. I've ordered a set of those plugs. Your comment about "will it be harmful to the ESC" - re sparking I'm sure is correct. CC in their support state the "spark is your friend". But that is still not the question which was will the ESC be affected by a brief on/off/on interruption when connecting.

[nightflyr]

Sorry I thought I made it understood.
Once the caps are charged, then your anti spark lead is replaced....
Granted the caps will discharge a bit between motions, the amount depending on how long it takes, but the input surge will be less.
So no you will not cause an issue.
In the same respect, my setups do the same thing...
Charge up the ESC caps through the anti spark on a momentary switch.
Once charged, the switch is released which is the same as you removing your lead, then the main packs are plugged in.

After better than 4 years I have yet to have an issue with any of my ESC's

[npomeroy]

OK.... Now it's clear.
In post #4: "I flip the switch to charge up the ESC, then connect the main packs.
Then switch off the resistor." ... does suggest the resistor is still connected when the main packs are connected.
Anyway, I've ordered that connector. Maybe I won't install it - Just briefly bridge the connection via resistance - then do the pack connection.

[npomeroy]

My spark-arresting connectors arrived today. Some hints for others that may get them: They are so bulky that I couldn't get a decent solder joint with a 25W soldering iron (i.e. the heat soaked away to quickly). This is accentuated in that you need to attach the female socket to the male part during soldering to disperse the heat, otherwise the insulated ring (on the male resistor-containing plug) can melt (I read this in a HK review of the product). An 80W iron was plenty to get enough heat into the joint.