As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PRIOR TO INSTALLATION, AN ELT WAS NOTED TO BE HOT. INVESTIGATION FOUND 4 OF BATTERIES WERE SHORTED DUE MIS-ASSEMBLY OF THE ELT CASE HALVES. SUBMITTER STATES MIS-ASSEMBLY IS EASY TO DO WHEN BATTERY INSTALLATION INSTRUCTIONS NOT FOLLOWED.