Problem is most people dont have a clue how long the engine has to run to fully charge a battery and think that a 15 minute run is enough. In reality if your battery is half charged it will take hours running to get it to full because the charging current drops of sharply as the battery voltage rises.
I suspect that this is less of an issue with modern alternators. There are a number of references to modern charging systems on TM recently.
No or at least not really. The issue is that the current flow is dependant amongst other things on the voltage of the battery itself so that as the battery voltage rises the current falls. Your 60 amp alternator could easily only be chanrging at 10 amps or less as a result.
I did some monitoring on my boat and it was several housrs to get a half charged battery near full with a 60 amp nominal alternator
