As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BATTERIES LEAKED ACID/ALKALII, CORRODING CONTACTS SERVERLY AND RENDERING ELT INOPERABLE.BATTERIES WERE INSTALLED IN 2006. SHELF DATE ON BATTERIES WERE MAR 2011. ELT WAS NOT FOUND ACTIVATED. THIS IS THE THIRD CASE OF THIS I HAVE SEEN IN 2006/2007 AND THERE HAVE BEEN SEVERAL OTHERS IN THE PAST 5 YEARS. IN ALL CASES THE BATTERIES RENDERED THE ELT INOP PRIOR TO THE REPLACEMENT DATE (HALF OF SHELF LIFE I/A/W FAR 91.207 (C)). ALL PROBLEMS WERE DETECTED DURING ANNUAL INSPECTIONS OF ELT I/A/W FAR 91.207 D.