The voltmeter reading on my C-7 has consistently been in the 14.2 to 14.6 range since I took delivery in late March. Starting today, it is now reading around 12.8 to 13. Even though this is not necessarily an abnormally low reading, it seems odd that it would change so suddenly. The only accessory being used is the radio. Does anyone have any thoughts ? Am I being too much of a worry wart?