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