B&K Precision 601B Tester, Battery, Handheld, SLA Battery Capacity Analyzer, 6V and 12V Overview The 600B and 601B Battery Capacity Analyzers address the need to test and maintain sealed lead acid (SLA) batteries used in backup power UPS, emergency lighting, fire alarms, security systems, and many other electrical systems. By quickly characterizing a battery’s response to a load resistance, th..