Rodney

Yes, your problems sure seem to be connectors. As to that spark you saw, that is pretty typical anytime you connect the battery to the ESC, more obvious with the higher cell counts, when you have 6 cells, it can be quite startling. That is because there is a capacitor on the input to the ESC and when you first connect to it, it is literally a short circuit for the first micro second or so as it starts charging that capacitor. On some of the larger capacity high cell count setups, the operator often installs a secondary connection buffered with a resistor to charge the capacitor before making the final connection to eliminate that spark that can and does erode the contact area on the high current devices.