Dapimpilator

Okay so last night as I was getting on the highway, this car was going about 45 in front of me and i was in a hurry to catch up with some friends so I punched it and went around them. I looked down at my gauges afterwards and noticed my battery light had come on, which is very strange to me because I have replaced the alternator maybe a month ago. Also I have only raced it maybe 6-7 times since then. Any ideas?