Manual

26
PART 3
TROUBLE-SHOOTING, AVOIDING BATTERY DEGRADATION AND
RECOGNIZING PROBLEMS
SECTION 1 - HOW TO AVOID BATTERY DEGRADATION
1.1 General Information and Precautions
Properly maintained and charged, Liberty Series 1000batteries will
provide many years of trouble-free service. However, despite their
inherent dependability, failure to operate and maintain them correctly
can lead to damage, shortened service life or cause loss of service.
The following sections address some of the most frequently
encountered errors.
1.2 Float versus cycle life
Standb
y batter
ies are designed and constructed to provide long life in
contin
uous float service. They differ in their design from “cycling
batteries,” such as “star
ting” or “traction” types. Standby batteries are
continuously charged at a compar
atively low float voltage in parallel
with the load, ready to supply instantaneous dc power either directly to
the load or by way of interf
acing electronics, such as an un-interruptible
power supply (UPS) system. The name “stationary” implies the battery
is usually permanently placed in a given location and not transferred
from place to place in its ser
vice life.
Standby battery calendar life is affected by and may be reduced by
repeated cycling.
Depth of discharge, number of discharges
, rate of
discharge, and the interval between discharges are some of the
determining factors in battery life. Cycling should therefore be kept
to a minim
um.
To ensure that the battery will perform during power outages and other
emergencies
, it is strongly recommended that testing be k
ept to a
minim
um in accordance with the f
ollowing practices:
• The performance of an initial acceptance test not to exceed user’s
or
iginally specifi
ed system reserve time.
• A full-load service test should be performed not more than once
every 12 months to verify battery capacity at user’s originally
specifi
ed discharge r
ate.
• A monthly transfer test not to exceed 30 seconds of battery
discharge time at user’s originally specified discharge rate to verify
system load tr
ansfer and electrical system performance. The time
that is required to synchronize the UPS system and return to rectifier
power must be taken into account when calculating total discharge
time
.
The user is expected to maintain complete records of all battery
testing and emergency discharges in order to comply with the
requirements of the warranty.