I have a 2006 Ford focus...last night it behaved as if the alternator went bad
the lights went dim, the radio said "Low Battery" and cut off...we got it home, and when I went to restart the car, the battery was dead...I jumped it, put a voltmeter to the alternator and it came out 8.6.It ran for awhile, but eventually stopped, again battery dead...Today, I disconnected the negative battery terminal as I was thinking of taking the alternator to Auto Zone to get tested, but due to its location, it was too difficult a job....So I jump started it and took it to a local mechanic, he put the voltmeter to it and it tested fine 14.2...Since the battery is over 5 yrs old, I put a new one in....started it, put the voltmeter to it, 12.5 then after about 30 seconds or so went to 14.23 and stayed there.The only "work" I did was disconnect/reconnect battery terminals....What is going on???? Can an alternator work intermittenly before it fails completely?? Is there something else that should be tested? Or can this all be from a failing battery????