C&D Technologies UPS12-100MR Maintenanse Instructions page 16

TABLE 1-VRLA Battery Symptoms and Solutions (Continued)
Symptom
DC VOLTAGE
CHECKS
(CONTINUED)
DC voltage measured
between either of the
battery system output
terminals and ground
(rack) or a ground
fault indicated by
automatic monitoring
equipment.
AC RIPPLE
VOLTAGE
CHECKS
AC ripple (p-p)
voltage on
the system is
greater than
4% of the value
of the DC
float voltage.
Individual battery
in string
exhibits AC
ripple voltage
of twice that of
the other
typical batteries
in string.
41-7546/0213/CD
Possible Causes
Damaged battery
container allowing
electrolyte to
wick out to
the grounded
surface (rack).
Poor filtering of the
charger output.
Battery with the
high AC ripple
voltage has a
proportionately
higher impedance
and should be
further evaluated
for performance.
Subject battery
could have a
deteriorating
conductive
path or a dry,
shorted or
open cell.
Possible Result
Personnel shock hazard
which could result in
serious injury or
electrocution.
Potential burning of the
container at damaged
area or battery fire.
Excessive AC ripple
could cause the battery
to cycle at the ripple
frequency and result in
heating and deterioration
of the plate
active material.
Reduced
operating time.
Potential conditions
could be conducive to
thermal runaway.
16
Corrective Actions
Determine the source
of the ground fault and
replace battery.
Improve the charger
output filtering.
Verify the battery
condition and replace
as required.
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