As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: BATTERY DISCHARGE LIGHT ILLUMINATED WITH A MASTER CAUTION LIGHT. AFTER 15 MINUTES LIGHT EXTINGUISHED. FLIGHT DECLARED AN EMERGENCY, DIVERTED TO PHL, LANDING SAFELY. REPLACED MAIN BATTERY (AALA202207270462) AND BATTERY CHARGER (AALA202207277885) PER AMM 24-31-11 AND AMM 24-31-21. ACCOMPLISHED SATISFACTORY OPERATIONAL CHECK.