Lawrence Berkeley National Laboratory

Some white light-emitting diode (LED) light sources have recently attained levels of efficiency and cost that allow them to compete with fluorescent lighting for off-grid applications in the developing world. Additional attributes (optics, size, ruggedness, and service life) make them potentially superior products. Enormous reductions in energy use and greenhouse-gas emissions are thus possible, and system costs can be much lower given the ability to downsize the charging and energy storage components compared to a fluorescent strategy. However, there is a high risk of "market-spoiling" if inferior products are introduced and result in user dissatisfaction. Complete systems involve the integration of light sources and optics, energy supply, and energy storage. A natural starting point for evaluating product quality is to focus on the individual light sources. This report describes testing results for batches of 10 5mm white LEDs from 26 manufacturers. Efficacies and color properties are presented.