Designing and testing battery charger systems for California's new efficiency regulations

The State of California has adopted tough new energy efficiency standards for battery charger systems. These regulations promise to save cost, energy, and greenhouse gas emissions, but they also present new challenges to engineers and managers involved in the planning, design, and system integration of battery charger systems. This paper aims to provide guidance by explaining the requirements of the standard, demonstrating proper test methods, analyzing real-world test results, and discussing significant factors affecting compliance. Experimental results and lessons-learned are presented for modern industrial lead acid battery charge systems. Although charger hardware conversion efficiency is important, the software algorithm is at least as important, as is the efficiency of the battery itself, and the system interconnections and cabling. Some charger topologies and battery types will struggle to comply with the standard, and may be displaced by more efficient technologies.