I have a 2003 mazda protege and it is having a problem. Sometimes when i go to start it it just won't start, theres no sound like its trying, just acts like i moved the key to the acc notch. Its done this 3 times now and each time if i hook it up to a charger for like a minute and try to start it again it works. Obviously the battery is not dead since it starts after a minute of charging... anyone have any idea what the problem is and if it is serious????