010-592-B2 Rev E
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6.6
Audible Alarm
The Audible Alarm switch is located inside the unit below the status LEDs. Its default position is OFF. If enabled,
the audible alarm gives a low battery warning of four short beeps once an hour when the battery string voltage
reaches 46.8V. When the voltage is between 40 and 46.80V, it takes 10 seconds to activate. When voltage is less
than 40V, it takes 30 seconds to activate. Silence the alarm for 24 hours by pressing the blue Silence Alarm
button on the front panel of the FMPS.
The audible alarm can be disabled by setting the Audible Alarm switch back to the OFF position.
6.7
Battery Backup Mode
In the event of an AC power outage, the FMPS switches to Battery Backup mode and the Battery LED lights. The
FMPS runs in Battery Backup mode until AC power is restored, or until the battery strings reach a low-voltage
shutdown level of 42V. On resumption of AC power, the FMPS will recharge the batteries at a maximum current
of 1.8A per string.
6.8
Charging Mode
Under normal conditions a float charge maintains the batteries at 100% capacity. If the unit operates in Battery
Backup mode, battery charging resumes when primary power is restored. Charging continues until one of the
following occurs:
•
Battery has reached 100% of capacity.
•
Another power failure occurs requiring battery support. Charging ceases until primary power is restored.
•
Additional power is required by the ONT, in which case power is diverted from the battery charger and sent to
the ONT. When demand for additional power ceases, normal battery charging resumes.
•
The battery is depleted. No special actions are required to restore normal operation once primary power has
been restored.
CAUTION!
Never connect batteries, or any other power source, to the output of the FMPS.
6.9
Battery Management
Batteries have limited shelf life and must be put into service in a timely manner. The chart below provides general
storage guidelines and illustrates the relationship between capacity retention and storage temperature over time.
Consult battery documentation for product specific information.
Figure 1
2
–Battery capacity characteristics
NOTE:
Should the batteries freeze during periods of cold weather power failure, a “battery missing” alarm will become
active until the batteries thaw.