What was found
AFTER LEVEL OFF AT FL390, APPROX 20 MIN AFTER T/O GOT LVL 1 BATT LOW ALERT. DIVERTED TO KLAS BATT SHOWED AMBER BOXED 8 OR 7. REMOVED AND REPLACED A/C BATTERIES IAW AMM 24-34-02-4. PERF DC TIE BUSS OPS CHECK. REMOVED AND REPLACED BATTERY CHARGER. REMOVED AND REPLACED BATTERY AMMETER SHUNT S4-1 RELAY, BAT CHARGER TRANSFER R2-217, RCCB BATTERY CHARGER B1-157, AND REPLACED PLUGS P1-1957, P1-1958, AND P1-1959 PER SWP. PERFORMED WIRING CHECKS PER AWD 24-33-01. PERFORMED EMERGENCY POWER TEST WITH NORNAL FINDINGS. STARTED APU WITH NO FAULTS AND BATTERY RECOVERY NORMAL AFTER START. RAN ALL 3 ENGINES PER JRH AND POWERED ALL 3 BUSSES WITH NORMAL RESULTS D/C SYSTEM CHECKS NORMAL.