As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAKEOFF ROLL AT APPROXIMATELY 40 KIAS, CREW RECEIVED A BACKUP BATTERY OFF BUSS INDICATION FOLLOWED BY NO TAKEOFF CONFIGURATION WARNING. THE TAKEOFF WAS ABORTED AND THE AIRCRAFT RETURNED TO THE GATE WITHOUT FURTHER INCIDENT. MAINTENANCE FOUND AND REPAIRED LOOSE CONNECTION ON BACKUP BATTERY BUSS IAW AMM 24-35-00. ALL SYSTEMS CHECKED GOOD, AIRCRAFT WAS RETURNED TO SERVICE.