Alternator / charging problem

[SteveQ]

Last night I moved the coach from home to work. When I started it there was no
alternator charge, usually there is about a two second delay from start to
charge showing on the gauge. On the trip I hit a bump and there was charge for
about 30 seconds then none. Both alternators are new as of three years and
about 20,000 miles. To me it sounds like a ground problem. Also I ran the
generator and the coach charge came up to about 10 amps

Where to start to solve the problem?

Thanks
Steve Quandt
1993 PT-40
Iron Mountain, MI