ESS_WG_1562 - Working Group for Energy Storage Subsystems

Curtis Ashton

IEEE-SASB Coordinating Committees

This guide is specifically prepared for a PV/engine generator hybrid power system, but may also be applicable to all hybrid power systems where there is at least one renewable power source, such as PV, and a dispatchable power source, such as an engine generator. Taper-charge parameters for PV hybrid systems are suggested to help in preparing the battery for a capacity test. A test procedure is provided to ensure appropriate data acquisition, battery characterization, and capacity measurements. Finally, a process to review test results and make appropriate decisions regarding the battery is provided. No cycle-life predictions are made.

A method for determining the energy-capacity requirements (sizing) of both vented and valve-regulated lead-acid batteries used in terrestrial stand-alone photovoltaic (PV) systems is described in this recommended practice. Sizing batteries for hybrid or grid-connected PV systems is beyond the scope of this recommended practice. Installation, maintenance, safety, testing procedures, and consideration of battery types other than lead-acid are beyond the scope of this recommended practice. Recommended practices for the remainder of the electrical systems associated with PV installations are also beyond the scope of this recommended practice.

This guide is applicable to lead-acid batteries that are used as the energy storage component in remote hybrid power supplies. The remote hybrid application, with its dual generator option, i.e., both renewable and dispatchable generation, is advantageous in that the battery can usually be charged at will and under circumstances that may also be advantageous for the dispatchable generator.

This guide is specifically prepared for a PV/engine generator hybrid power system, but may also be applicable to all hybrid power systems where there is at least one renewable power source, such as PV, and a dispatchable power source, such as an engine generator. Taper-charge parameters for PV hybrid systems are suggested to help in preparing the battery for a capacity test. A test procedure is provided to ensure appropriate data acquisition, battery characterization, and capacity measurements. Finally, a process to review test results and make appropriate decisions regarding the battery is provided. No cycle-life predictions are made.

Provided in this recommended practice is information to assist in sizing the array and battery of a stand-alone photovoltaic (PV) system. Systems considered in this recommended practice consist of PV as the only power source and a battery for energy storage. These systems also commonly employ controls to protect the battery from being over- or under-charged and may employ a power conversion subsystem (inverter or converter). This recommended practice is applicable to all stand-alone PV systems where PV is the only charging source. This recommended practice does not include PV hybrid systems nor grid-connected systems. This recommended practice covers lead-acid batteries only; nickel-cadmium and other battery types are not included. This recommended practice does not include the sizing of the system controller, inverter, wiring, or other system components.