My battery had corrosion on post and I had to get a.jump. No battery light and gauge normal. Cleaned post & that lasted about 3wks. Then just didn't start out of the blue. had to get a jump. this time battery light come on and gauge was waaay on the low side. Put a new battery in but light and gauge still on & low. put new cable ends on and still no change. put tester on and battery was 12 and alternator was 14. other than alternator what could it be?