Q: Battery problems with jeep

A few weeks ago, my Check Engine light came on. Then a week or two later, both of my low beam headlights went out, though the high beams and all of my rear lights still worked. I had my battery checked, and it was still good, though a little low. The shop charged it back up for me. As I was leaving work the other night, I noticed that after I turned on the high beams, my dashboard lights started to dim and the battery volt gauge on the dashboard dropped below 9 volts. My jeeped began making a clunky guzzling noise and started to slow down before stalling.