charging

There seems to be a lot of issues with the 332 charging system (mine also has issues) Has anyone successfully swapped the OEM alternator and Reg/Rec to a single wire internally regulated alternator? I know there doesn't appear to be much room but there are some very small alternators out there...

My 1987 JD 316 with Onan P218G engine does not appear to be charging the battery reliably. Does someone have a circuit diagram and procedure for testing the alternator/charging circuit that they can share with me? Thanks in advance for your help! DJ