Radar Detector Picking Up Spikes in Voltage

Hey guys. I have a Bel Pro 300 radar detector that detects voltage on my 04 RX8 (110k miles). This morning I turned on my lights as I was driving and it alerted me of the spike in voltage. As I was driving to work I noticed the voltage was all over the place as I was cruising. Lowest was around 10.4 and highest was 16.2. Normally it fluctuates between 12.2 and 14.8. Is it possible that I am at the beginning of an alternator failure? I know that they usually give no signs that they are going out.



Thanks,