JD 345 charge light

[Ifixcars]

Hello, I am posting this for a friend. He has a 345 that has the battery light on when running. He says it has been on for a month now. It starts right up, and will run fine for hours while he cuts his grass. He does not have to jump start it or charge the battery with a charger. I told him to check the charging voltage with a meter and get back to me. He said he would do that this week sometime. I though I would ask if there are any known problems with these models. He did say he checked his fuses and they were not blown. Any help or tips would be appreciated.