Lucent Technologies Lineage
®
2000 ECS/GPS Battery Plant J85500G-2
Issue 6 May 1999
Engineering, Planning and Ordering 3 - 7
The noise and transient filtering capability of batteries, however,
may also be considered in selecting the minimum battery
capacity. Many using systems specify the maximum allowable
input noise. Applications (such as UPS-supplied ac power)
which do not require batteries for dc reserve purposes may
require batteries or some other means for noise filtering.
Compare the input noise requirements of the using system to the
ECS Battery Plant specifications in Table 2-A.
Fill in the minimum reserve time below.
14. Minimum battery reserve time: ____ hours
Battery capacity is usually specified in terms of ampere-hours,
which is essentially a measure of energy. The ampere-hour
rating is the product of a constant discharge current and the time
to discharge a fully charged battery to a specified end voltage.
For comparison purposes, most vendors of telecommunications
batteries specify ampere-hour ratings at the 8-hour rate of
discharge to an end voltage of 1.75 volts per cell. Many battery
vendors also supply ratings at other discharge rates, such as 3-,
5- and 24-hour rates.
Although ampere-hour ratings are useful for rough estimates of
battery size, actual battery selection should be based on curves
or tables of discharge current versus time.
Charge capacity
and recharge time
For all but batteryless applications, rectifier capacity must be
provided specifically for the recharging of batteries. This
rectifier capacity must be engineered into the plant in addition to
that required to power the load under normal or float conditions.
Table 3-C: Reserve Capacity
Back-up Source
Typical Reserve Time
Attended Location
Unattended Location
Stationary Engine
(automatic start)
3 hours
3 hours + travel time
Stationary Engine
(manual start
4 hours
4 hours + travel time
Portable Engine
4 hours + travel time
Uninterruptible Power
Supply
0 hours (batteryless
