The problem with disconnecting the motor from the ESC is if you have one that is NOT color coded, then it's easy to get the leads mixed up and you could have a reverse running motor. Not that big a deal because all you have to do is swap any two leads and you're good to go (brushless that is). For brushed, well, red to red and black to black.

But, as already mentioned, I never disonnect them, just remove the battery pack, swap or re-charge, then put it back in.

I have a "LiPo Sack"... sold somewhere on the web.. that I charge my LiPo packs.. ALWAYS outside.

CGr.