I own a 2009 Dodge Challenger R/T. I got a weird reading on my tachometer screen that looked like 0039 or something with a 9 as the last digit. The car was having a weak start about every tenth start. I took it to a mechanic who told me my battery was not strong but that the charging system seemed ok. They replaced the battery. 2 days later upon starting I heard a high pitched whizzing/whining noise when the rpm were increased. I had to drive home so I got on the highway. I was on the highway when all the lights and guages starting going off, the lights dimmed and I smelled a burning smell. I was able to coast into a gas station where it completely died. Took it back to the same mechanic. After diagnosing, he claimed that he must've put a battery with a bad cell into the car. He replaced the battery (2nd battery) and the car drove strong. About two weeks later I noticed the screen on the tachometer (red lines) seemed illuminated slightly at night. I took it to AutoZone and O'reillys and they both said the charging system was bad. I then took it to the same mechanic to have him test it. His machine showed both the battery and charging systems were fine. It's now a week and a half later and as I was driving home tonight the battery light came on on the panel. The check engine light has never come on. I'm planning to take it to the mechanic again tomorrow! This must be the alternator,right? Has anyone experienced this scenario?