As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING START APU WON'T SPOOL UP WITH APU AND APU BATT MSG. MSG #49-10620. APU SPEED DID NOT REACH 7 PERCENT CAUSED AUTO SHUTDOWN. NO TIME FOR FURTHER WORK. C-B FOR APU BATTERY CHARGER PULLED AND COLLARED. DEFERRED PER MEL. -INF- :BATTERY CHARGER 566-0081. REPLACED APU BATTERY CHARGER PER MM AND RAN APU OKAY.