IEEE 1013-2007 pdf download IEEE Recommended Practice for Sizing Lead-Acid Batteries for Stand-Alone Photovoltaic (PV) Systems
1.Overview
This recommended practice provides a systematic approach for determining the appropriate energycapacity of a lead-acid batery to satisfy the energy requirements of the electrical loads of a stand-alonephotovoltaic (PV) system. Since this capacity determination (sizing) assumes that no power isavailable from the array, the resulting battery capacity should be more than adequate to meet the Pysystem’s load requirements during its normal operation.
1.1 Scope
This recommended practice describes a method for sizing both vented and valve-regulated lead-acidbatteries in stand-alone PY systems. Installation, maintenance, safety, testing procedures, andconsideration of battery types other than lead-acid are beyond the scope of this recommended practiceSizing batteries for hybrid and grid-connected PV systems is beyond the scope of this recommendedpractice. Recommended practices for the remainder of the electrical systems associated with standalone PV installations are also beyond the scope of this recommended practice.
Sizing examples are given for various representative system applications. Iterative techniques tooptimize battery costs, which include consideration of the interrelationship between battery size, Pyarray size, and weather, are beyond the scope of this recommended practice.
1.2 Purpose
This recommended practice is meant to assist system designers in sizing lead-acid batteries forresidential. commercial, and industrial stand-alone PV systems.
2. Definitions, acronyms, and abbreviations
For the purposes of this recommended practice, the following terms and definitions apply. TheAuthoritative Dictionary of lEEE Standards Terms (B1′ should be referenced for terms not defined in
this clause.
2.1 Definitions
2.1.1 array-to-load ratio: Average daily photovoltaic ampere hours (Ah) available divided by theaverage daily load in ampere hours.
NOTE–The average daily photovoltaic (PV) ampere hours is calculated by taking the average daily solarresource for the month of interest in kilowatt hours per square meler (kW/m’) times the array current at itsmaximum power point (/mp) under standard test conditions (STC).
2.1.2 autonomy: The length of time that a photovoltaic (PV) system can provide energy to the loadwithout energy from the PV array.
2.1.3 regulation voltage: The maximum voltage that a charge controller allows the battery to reachunder charging conditions.
2.1.4 solar irradiance: Instantaneous power density of sunlight measured in watts per meter squared(W/m’).
2.1.5 solar radiation: The time integral of solar irradiance.NOTE–Solar radiation data for a geographic location is generally reported for each month as the average dailyradiation for a specific array tilt angle. A typical range for daily solar radiation is 2 kW/m’ to 7 kW/m.
2.1.6 standard test conditions (STC): The accepted conditions under which photovoltaic devicesare commonly rated: 1000 W/mirradiance at a spectral distribution air ass (AM) of 1.5 and a 25 pV cell temperature.
2.1.7 sun hours: Length of time in hours at a solar irradiance level of 1 kW/m’ needed to produce thedaily solar radiation obtained from the integration of solar irradiance over all daylight hours. Sun hoursis sometimes referred to as peak sun hours.