Is it bad when I see a little spark on the Deans Plug when connecting my battery to the ESC?

Probably not a good thing, but it’s pretty common these days with the large external capacitors on the speedos. They are directly connected to the battery leads, need to be charged up.

A bunch of us see the same thing. Never been a problem and yes from what I have heard it's due to the large capacitor on the esc.

Alright thanks. That's all I needed to know.

NEVER use a cap on a Castle Creations ESC you will cause damage to the ESC.

The small spark is fine, you should see the spark from connecting 12S lipo to something...

I use 3300Uf cap on my MM to run 4S and up and its never had a prob - it gets a little warm though. Go over to RCMonster - there's plenty running caps on the MM to enable running higher than spec voltage. Of course the voids the warranty, but if it works....

I run 3 x 3300uf caps on my Quark 125b and that is NOT a little spark on 6S, lol!! Its a loud enough zap that when I make the 1st connection for the day, questions get asked, hehehe. Seriously, BrianG, mod on RCM has a sticky showing how to run a resistor and let caps charge thru the resistor so you don't get the spark. That will save your Deans if you're running HV setup.