Every once in a while my battery drains like really fast. It'll be maybe half way charged... and like 10 minutes or so later the digital gauge all of a sudden jumps from half way, to basically one or two notches! I'm not sure if something is wrong with the car's system or... I was thinking that maybe this happens when the ECON a/c on for 10 minutes or more. Does anyone know if the ECON a/c will drain the battery really fast?