After discussing with Company Maintenance and Management their inability to rectify a battery fault light; which appeared on their arrival to an intermediate stop; the flight crew of an SA227 was pressured by the managers to continue to their next scheduled stop without resolving the fault light warning. The reporter refused to go but the Captain agreed to do so. While enroute the Captain was confronted by a wing overheat light--attributed by the reporter to have been caused by an 'electrical problem'--and had to shut down the left engine; declare an emergency and divert.

Narrative

In cruise flight we experienced a battery fault light; which detects problems within the electrical system. We ran through the checklist and the light was not extinguished. We continued to our destination because we were now only about 15 NM away. We landed with no issue and then performed the checklists again; called Maintenance; the Chief Pilot and the Director of Operations. No one had a remedy. They insisted; however; that we continue the next leg of our sequence. I refused to go on the flight for legality and safety concerns. There were just too many factors adding into a possible problem. The weather was marginal; it was the PIC's first flight as a Captain; and the [battery fault] light was an issue. My Director of Operations insisted that I go and explained to me that it wasn't a big deal; and that it wasn't a problem. He asked me to break the law countless times within the conversation. But I refused to go. They talked the Captain into going and I stayed on the ground. During the Captain's flight he experienced a wing over heat light caused from an electrical problem and was forced to shut down the left engine and declare an emergency and divert.