Originally Posted by dbh
Here is the latest observations on my charging system.
This weekend on a nice long ride to the mountains and back I noticed the voltage display on my Garmin 276C started indicating a range of voltages between 12.6 and 14.0
So I checked with a digital multimeter and it read 14.33V steady.
Bottom line: don't rely on your 276C alone for a definitive diagnosis.
Do you have the GPS wired directly to the battery?