The 4542273 (Fluke BT521ANG) is an advanced battery analyzer designed for comprehensive testing and maintenance of stationary battery systems. It measures battery internal resistance, DC and AC voltage, DC and AC current, ripple voltage, frequency, and temperature with high precision across multiple ranges. The instrument features wireless communication capability via the Fluke Battery Analyzer mobile app for remote data download and display, automatic sequence testing of battery strings with up to 100 profiles storing up to 450 batteries each, and automatic measurement storage eliminating manual data entry. With measurement ranges including 3 mO to 3000 mO for resistance, 6 V to 1000 V for DC voltage, and 0 °C to 60 °C for temperature, the BT521ANG provides comprehensive diagnostics for UPS systems, power distribution, and critical infrastructure battery maintenance applications.