Battery Internal Resistance Tester Lead-Acid Alkaline Lithium Battery Tester 1. Voltage: 0.00V~120V 2. Internal resistance measurement: 0.000mΩ~500Ω 3. Input voltage: DC 120V (regardless of polarity), AC input is not allowed 4. Measurement current: 50mA~50uAAC 5. Measurement speed: 3 timessecond 6. Measurement signal frequency: 1KHz 7. Screen and size: IR500 55x57mmTN black and white screen; IR 502 55x57mmTN color screen 8. Power supply: 3.7V 1200mAh lithium battery 9. Automatic switching of internal resistancevoltage range 10. Can be used for various battery detection such as lithium battery, lead-acid battery, carbon battery, alkaline battery, button battery, etc. 11. 3.2-inch high-definition VA screen display, mainslave dual reading value 12. Kelvin four-wire detection is used to effectively avoid the influence of wire resistance and contact resistance, thereby ensuring the accuracy of measurement 13. TPR sheath is more shatterproof, and LED flashlight drives away darkness 14. The internal resistance value can be determined based on the lower limit condition "Lo" and the upper limit condition "Hi" set by the user, and the test results are classified into excellent, qualified, and poor to make a double alarm prompt with flashing graphics and sound 15. The lithium battery needs 2 hours to be fully charged, and a full charge works for about 8 hours 16. The instrument automatically shuts down if there is no button operation within 20 minutes 17. The host and the test clip are connected through the DB9 interface, where pin 1 is empty, pins 2, 6 and 5, 9 correspond to the red line and white line connected to the two sides of the red clip; pins 4, 8 and 3, 7 correspond to the yellow line and black line connected to the two sides of the black clip