Lucent Technologies 1200A 24V ECS Battery Plant J85500E-2
Issue 7 October 1998
Engineering, Planning, and Ordering 3 - 15
s. Determine the smallest whole number of rectifiers that
will provide the normal (List 1) plant drain in Table
3-A: ____
t.
Determine the smallest whole number of rectifiers that
will provide the normal plus recharge current from
Table 3-A and (q): ____
u. Provide the greater of (s)+1 or (t) rectifiers: ____
For batteryless plants, skip to paragraph “Initial and
Supplementary Bays.”
Battery Sizing
The battery type and minimum size are determined in
paragraphs “Battery Plant Voltage” and “Reserve Capacity.”
Many vendors offer families of batteries that cover a wide range
of ampere-hour capacities. Ampere-hour capacities of parallel
battery strings are added to provide the total reserve capacity of
the battery plant. To supply the necessary reserve, several strings
of small capacity batteries or one or two strings of large capacity
batteries may be connected in parallel.
There are several important considerations in the choice of
battery size versus number of strings, namely,
•
Cost
•
Weight and Space Efficiency
•
Anticipated Growth
•
System Reliability
Cost. The cost per ampere-hour decreases with increasing cell
capacity. On the basis of initial material cost, the number of
strings should be minimized.
Weight and Space Efficiency. Weight density and space
efficiency increase as battery capacity increases. There can be
significant differences in space efficiency, however, between
different vendors of the same capacity battery. Floor loading
restrictions may limit stacking of batteries. Structural limitations
of the building must be clearly understood before selecting a
battery arrangement.
See paragraph “Floor Plan Data” for more information on floor
loading. Applications with space restrictions such as standard
aisle depths may dictate the use of more strings of smaller
batteries.
