I have a es8000 and it has been a good unit. It all of a sudden stopped charging while it was running under a very small load.how and what do I check first.Paramac es8000

This likely has a diode module which rectifies a low voltage AC winding to do the charging.

Things to check: There USUALLY is a fuse on the low voltage winding. It SOMETIMES is within the generator covering.

Check for loose connections or broken wires.

The diode module is usually a 25 amp block about 1.25 inches square with 4 faston terminal connections.

Use a meter set to AC to check voltage on the AC terminals... might be around 18 volts or so.

Then on the DC terminals labeled + and - with meter set to DC.

To charge a 12 volt battery there needs to be about 13.75 volts or so.