IEEE Std 485-2020 pdf free download

IEEE Std 485-2020 pdf free download.IEEE Recommended Practice for Sizing Lead-Acid Batteries for Stationary Applications.
B.1 General
When the battery sizing procedure and methods described in this recommended practice are used for the specified duty cycle and the celL size selected, the average ccli voltage does not drop below the specified minimum at any point in the duty cycle. It is not, therefore, normally necessary to calculate the cell or battery terminal voltage because it remains above the predetermined allowable minimum throughout the discharge period. If the need for such information should arise, a method of calculating the voltage at various points in the duty cycle, utilizing the battery manufacturer’s typical discharge characteristic curves, is described in 13.2 and 13.3.
B.2 Method
Two types of typical discharge characteristic curves in common use are “fan” curves and “S” curves, typical examples of which are shown in Figure B. 1 and Figure B.2, respectively. Although these two curves have difFerent coordinates and appearance, they show comparable data for two different cell types.
The method of calculation (using either curve) is an iterative process and consists of the following:
a) Keeping a cumulative total of the ampere-hours ‘removed” from the cell during each discharge segment/period
b) Identifying the discharge current at that time
c) Using this information, along with the battery manufacture?s typical discharge characteristics, to determine the cell terminal voltage at various points in the duty cycle
The voltage/time profile is then a plot of these cell voltages versus time for the entire duty cycle. To determine the voltage just before and just after a step change in the discharge rate, keep the cumulative ampere-hours constant and determine the voltage based on the two different (before and after) discharge rates. The battery terminal voltage at each point is equal to the average cell voltage multiplied by the number of cells connected in series.IEEE Std 485-2020 pdf free download.