The Optimate TS120 Battery / Alternator Tester helps you check the condition of your 12V lead-acid or 12.8V LiFePO4 starter battery and confirm alternator output during engine running. You use the built-in LED indicators, automatic voltage recording, and wide testing range to assess charge level, cranking voltage and charging voltage with quick on-vehicle checks.Discover the key features of this tester:State of Charge LED Display: A fully enclosed electronic LED panel presents green and red indicators that show battery charge status by monitoring open-circuit voltage, helping you identify a weak battery before you start the engine and allowing you to act early to prevent starting issues.Cranking Voltage Recording: An automatic voltage-logging function measures and stores the lowest cranking voltage for 20 seconds using internal circuitry calibrated to read down to 6V, giving you accurate insight into the battery s starting performance and helping you diagnose voltage drop problems that