IEEE Std 1013:2007 pdf free download

IEEE Std 1013:2007 pdf free download.IEEE Recommended Practice for Sizing Lead-Acid Batteries for Stand-Alone Photovoltaic (PV)Systems.
5.2 Load data
The systematic identification and characterization of the system’s indisidual loads are fundamental to defining the battery’s duly cycle. The information in 5.2.1 through 5.2,6 is provided to assist in gathering and charactcriring thc system’s loads.
5.2.1 Momentary current
Loads lasting I mm or less are designated “momentary” loads and are given special consideration. The ampere-hour requirements of this type of load are usually very low. but their effect on battery terminal voltage may be considerable and should be taken into account. Momentary loads can occur repeatedly dunng the duly cycle. Typical momentary loads arc:
a) Motor starting currents
h) High invcrtcr surge currents
5.2.2 Running current
Running current is the current required by a load after u.s starting current has subsided. Certain devices require a constant power. thus the required current rises as the battery voltage falls. For the typically long-rate discharges of PV applications, the battery’s voltage remains relatively constan until near the end of discharge (EOD) therefore, the running current may be approximated as the current required at 95% of the system voltage.
NOTE—For certain loads, it is necessary to consider both the momentary and running current components of the load. For csamplc. if an cketnc motor stalls dunng thc duty cycle, both the starting Imomentaryl current and naming current need to be considered. The starting current need fbi be considered if the load was operating at the beginning of the duly cycle. ic., at the beginning of the autonomy period
5.2.3 ParasItic current
Parasitic losses, such as those resulting from tale losses of charge controllers and inverters. should be included as currerns. These currents should be included as part of the running-current loads Consideration of the baitcry’s self-discharge, which is a parasitic current that depends on the battery type and capacity, is recommended as a check (ace 8.5) after the battery is selected.
5.2.4 Load duration
The load duration is the time, in hours, of operation of each load, For 1W systems, it is very common for load duration to be expressed in terms of a daily cycle that repeaLs over the days of autonomy. If the inception time of a load is known, but the shutdown time is indefinite, it should be assumed that the load continues through the remainder of the autonomy period.
5.2.5 Load coincidence
Iach load current i momentary or running) is classitied ax to whether or not it is coincident with any other loads and is tabulated accordingly. Loads that occur at random are assumed to be coincident loads. This information. portrayed in the load-profile diagram, is later used in battery selection and to check discharge rate (see 5.3).
5.2.6 Maximum and minimum load voltage
The maximum and minimum voltage at which each load device operates properly should be detemiiiied and tabulated isee b.2). Voltage drops. such as those associated with cabling. tnercurrenr protection, and connectors, between the battery and the loads are not to be considered as an adjustment.