DJRoy,
we seem to have two themes going here, one that your battery is being drained overnight and the other that your charging system is not working. I will comment on the charging system.
First, once the generator is polarized, it will stay that way.
If you grounded the field on the generator and the battery terminal on the regulator was showing 7.5 volts while above idle, then your generator is working. I specifically mentioned the voltage at the battery terminal on the regulator. Now, if the field was grounded at the generator during the test and not at the regulator, it is possible that the wire connection between the generator field and the regulator field terminal is broken. That is why I suggested doing the test with the ground applied at the regulator terminal. If you do so and the results are the same then I would replace the regulator.
