What was found
CABIN EMERG LIGHT: DURING FLIGHT FROM SEATTLE TO BOISE IN THE CLIMB THROUGH APPROXIMATELY 27,000' THE CABIN EMERGENXY LIGHTS (OVERHEAD, SIGN AND FLOOR) STARTED FLICKERING. THIS WAS THE 3RD LEG OF THE DAY AND HAVE HAD NO ISSUES ON ANY PREFLIGHT OR LEG PRIOR TO THIS FLIGHT. CORRECTIVE ACTION: REPLACED #2 EMERGENCY BATTERY IAW EMB-505 AMM 33-52-01. OPS CHECKS GOOD IAW AMM 33-52-00 NO DEFECTS NOTED, OK FOR SERVICE.