Sealey digital battery alternator tester 6 12v battery 6 12 24v alternator sealey bt2002 digital tester from sealey ideal for the professional diagnosis of battery and alternator faults connect and follow the prompts on the lcd screen for straightforward answers incorporates a simple voltmeter for voltage tests and additional system diagnostics sealey bt2002 digital battery alternator tester 6 12v battery 6 12 24v