In terms of performance, batteryless systems will generate more energy than battery-based ones. How much more will depend on the charging source (solar, wind, or hydro-electric), and the power-conditioning equipment (inverters and controllers) used. The condition of the battery pack and how frequently and deeply the battery pack is cycled comes into play too. Some energy, in the range of 5% to 20%, will be lost in the electrical-to-chemical storage process that takes place when charging batteries. But because batteries are rarely cycled in most battery-based grid-tied PV systems, the overall system efficiency hit can be pretty minimal (5% to 10%) if high-quality equipment is used. Batteryless wind systems can significantly outproduce battery-based ones due to some interesting electrical details covered in the following pages.
