C&D Technologies UPS12-100MR Maintenanse Instructions page 13

TABLE 1-VRLA Battery Symptoms and Solutions (Continued)
Symptom
High current
recharge.
VISUAL BATTERY
CHECKS
Cover/container
crack.
Cover/container
explosion.
Burned area on
container.
Permanently
deformed (swollen)
container.
41-7546/0213/CD
Possible Causes
High charging
voltage.
Shorted cells.
Handling or impact
damage.
Ignition of cell
internal gasses due
to external source,
fusing of internal
conductive path, or
internal spark due to
shorting. This potential
exists for batteries not
maintained and
continued in service
beyond useful life.
Crack in container
wicking electrolyte
to grounded rack,
etc.
Ground fault.
Thermal runaway
possibly caused by
high temperature
environment,
overcharging,
excessively
high recharge current,
shorted cells or a
ground fault or a
combination of
these items.
Possible Result
This combination can
lead to thermal
runaway.
Cell dryout or ground
fault. Potential internal
gas ignition.
Personal injury and
equipment damage at
time of explosion.
Failure to support load.
Could result in personal
hazard due conductive
path to rack, etc.
Could result in smoke or
a battery fire.
Could result in a thermal
runaway.
Could result in the
emission of hydrogen
sulfide which is
detectable as a rotten
egg odor, battery fire
and inability to support
the load.
13
Corrective Actions
Limit recharge current.
Reduce to within
specifications.
Replace shorted cells
and evaluate total string.
Replace damaged unit.
Replace damaged
unit and evaluate the
balance of string.
Clear the ground fault
and replace defective
unit. Evaluate balance
of the string.
Replace the battery
system and correct the
items leading to the
thermal runaway
condition.
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