Taming the dreaded 10s spark

As some of you large scale guys may know, you get one heck of a spark when you plug in an 8-12s setup. And Castle escs do not like slow charge up, so i thought why not put one of these http://www.robotmarketplace.com/prod...-SWHELLA2.html between the batteries and the esc so that you can plug your packs in and then flip the switch to let all of the voltage flow through the already connected wires to avoid the spark. Am i right on this? I mean the spark is from the caps charging up; correct?

[josh9mille]

Its going to spark no matter what. You are just moving the location of the spark to the inside of a switch rather than the battery connector. As far as i know the spark is harmless.

[What's_nitro?]

Triac switch.....

[simplechamp]

Originally Posted by What's_nitro?

Triac switch.....

TRIAC stands for "Triode for Alternating Current", so can it even be used to switch a DC load?

[OldGuyBL]

I hate to say it but, I love the spark! There is just something absolutely wicked about the sound and look of all that power! Watch some newbies eyes bulge out when you connect and enjoy an evil chuckle.

[doo540]

A easy fix is to move up to 12s setup. Then the 10s spark wont seem so bad. haha

[What's_nitro?]

Originally Posted by simplechamp

TRIAC stands for "Triode for Alternating Current", so can it even be used to switch a DC load?

Of course it can!

It's just two SCRs connected inversely so it can conduct current in both directions. You could just use one SCR, but a Triac would allow for regenerative braking.

Seriously would it still spark just as bad if you had a switch turned to off when you connect the batts? The spark is completely harmless, it can seriously pit the connectors. Due to my limited hand strength, i usually need someone to connect them for me, which is difficult when there scared.

[BrianG]

A triac has a ~0.7v drop so the power dissipated at ~20A would be 14w - not a small amount. Also, you would need quite a large triac to handle the 150A+ bursts without damage. If anything, a smaller triac could be used to get the caps charged up, then connect the main wires together (bypassing the triac) for running.

If you still want to go this route, I'd use a small bank of FETs to do the switching. That way, you can keep it in the circuit with minimal losses if you really want to use it while running.

[BrianG]

Originally Posted by Fast5sRevo88

Seriously would it still spark just as bad if you had a switch turned to off when you connect the batts? The spark is completely harmless, it can seriously pit the connectors. Due to my limited hand strength, i usually need someone to connect them for me, which is difficult when there scared.

Yes, the spark is still there because no matter if the ESC is on or off, the caps are the parts that cause it.

[simplechamp]

Basically the spark would just be transferred from the connectors to the switch contacts, and they would still get pitted after awhile.

[BrianG]

Maybe use a parallel set of "sacrificial" contacts? Something easier and cheaper to replace?

[What's_nitro?]

Originally Posted by BrianG

A triac has a ~0.7v drop so the power dissipated at ~20A would be 14w - not a small amount. Also, you would need quite a large triac to handle the 150A+ bursts without damage. If anything, a smaller triac could be used to get the caps charged up, then connect the main wires together (bypassing the triac) for running.

If you still want to go this route, I'd use a small bank of FETs to do the switching. That way, you can keep it in the circuit with minimal losses if you really want to use it while running.

Hey I didn't say it was practical...

Originally Posted by OldGuyBL

I hate to say it but, I love the spark! There is just something absolutely wicked about the sound and look of all that power! Watch some newbies eyes bulge out when you connect and enjoy an evil chuckle.

I am there with ya on that one. I went to the local flying club and watched this guy connect the plugs on his Trex 700 and boy what a show. Love it. I use extra caps on all my ESCs and get a decent spar too. Just change the connectors more often. No big deal, and keeping connectors fresh means lower resistance.

[lincpimp]

IIRC someone used to have a diagram of how to use a resistor on the neg side with a small bullet connector to let the caps charge slowly. I do remember pdelcast saying that was not good for a few of the cc escs...