Dead alternator or dead battery?. This compact and easy-to-use device includes three alternator readings (strong, normal, low) and three battery readings (good, fair, poor). Three alternator readings: Strong (14V), Normal (13.5V), Low (13V).
TOPDON BT50 12V Car Battery Tester 100-2000CCA Auto Battery Alternator Analyzer
12V Car Battery Alternator Tester Test Battery Condition & Alternator Charging