MP SERIES™ Battery Backup System for Traffic Signals: MP2000E System
Volume One: Operating Manual
Page 6-30
below the default or user-defined threshold. Figure 6-20 illustrates the relationship between
these conditions and battery voltage / run time.
Figure 6-20 is not to scale and all values and times are shown for illustrative purposes only.
To determine actual discharge rates under application-specific operating conditions perform a
Battery Back Up Time test. See Section 7.a.1 for instructions on performing this test.
Low Battery Mode States
Low Battery
Warning
The batteries will continue to power the load, but they are almost
discharged and cannot provide power much longer.
TIP: The operator should shut down unnecessary loads to extend battery
backup time
Low Battery
Shutdown
When the battery decreases to 42.5VDC for 3 seconds, the unit
automatically shuts output OFF and goes into SLEEP mode, waiting for
input power to return. The batteries are considered fully discharged and
can no longer support the load, but they have enough power to keep the
unit’s monitoring and control circuits active. The housekeeping power
supply is kept alive.
Low Battery
Disconnect
When the battery discharges to 40VDC for 10 seconds, the unit
automatically goes into this mode. The batteries are disconnected from
the unit to protect the batteries from being damaged by a deep discharge.
Both the LED and LCD shut OFF, showing the unit is shut off. The unit
stays off until line power or a backup generator is available or fresh
batteries are connected. If the BBS is to remain in a low battery
disconnect state for an extended period, the BBS and battery circuit
breakers must be switched OFF and the manual bypass switch must be
switched to the Bypass position to prevent battery damage. For
