Originally Posted by Kettlewell
I would roughly summarize possibilities with our limited knowledge in this order of things to check, assuming the light is indicating you are not getting an adequate charge:
1. Loose and/or worn belt slipping.
2. Corroded and/or loose connections somewhere either in alternator charging line to batteries or ground line (often it can be a bad ground). Clean and check all.
3. Batteries old and dieing.
4. Alternator on its way out.
Ya one of these sounds likely...
The belt was changed a week ago , it is perfect I think and not slipping.
All the connections I checked are like new, 2 fuses
at rear of alternator are good.
Batteries are 5 year old. Although they only show 12.8v when running engine they do not discharge very much. We used auto pilot, plotter,radio,and used inverter
to make coffee a few times and after 5 hours we were still 12.6v on the house batteries.
Maybe the alternator is bad but it has about 38 hours on it.
I will get my meter and figure out the alternator output tomorrow. Thanks all!