As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN FLIGHT WITH EMER LT SWITCH IN ARM POSITION, EMER LIGHTS STAY ON, ABOUT 45MIN INTO THE FLIGHT THEY BEGAN FLASHING DUPLICATED FAULT & FOUND BOTH OF THE EMERGENCY BATTERY PACKS WILL NO LONGER HOLD A CHARGE. REMOVED DEFECTIVE UNITS & INSTALLED OPERATOR SUPPLIED EMERGENCY LIGHTS BATTERY PACKS IAW AMM 33-52-01. ALL OPS CHECKS ARE GOOD. NO FURTHER DEFECTS NOTED.