Hey guy's I'm about to change my esc to series connection of the battery's. I guess I mean running 2 plug's on the esc to use say 2x 2s lipo's. Now when i do this I should go with the red + into the positive plug, run a new length of wire from the - to the other positive plug and wire the negative wire on the esc to the negative on the secong plug. Sound right?

Sounds right for a series 4S connection for more voltage. (your ESC can handle that right?) Here's a picture for reference: