Zoyi ZT-XR1 Digital Multimeter Battery Internal Resistance Tester . Unboxing and review of the Zoyi ZT-XR1 Digital Multimeter Battery Internal Resistance Tester. This 25,000 count True RMS multimeter is packed with professional features including AC/DC voltage, resistance, capacitance, continuity, diode, frequency measurement, and most importantly 4-wire battery internal resistance testing. In this video, we test: 🔋 Different types of batteries – AA, 18650, phone battery, power bank, Li-ion pac