NEC 500 UPS User Manual page 8

Replace Battery
If the battery fails a self-test, the UPS emits short beeps for one minute and the replace battery LED illuminates. The UPS repeats
the alarm every five hours. Perform the self-test procedure to confirm replace battery conditions. The alarm stops when the
battery passes the self-test.
100% Battery Charge Bar Graph
80%
The 5-LED display on the right of the front panel shows the present charge of the UPS's battery as a percentage of the
60%
battery's capacity. When all five LEDs light, the battery is fully charged. The top LED goes out whenever the battery is
40%
20%
not 100% charged. When the lowest LED is flashing, the battery can supply less than two minutes of run time for the
load.
Shutdown Mode
In shutdown mode the UPS stops supplying power to the load, waiting for the return of utility power. If there is no utility power
present, external devices (e.g., servers) connected to the computer interface or the accessory slot can command the UPS to shut
down. This is normally done to preserve battery capacity after the graceful shutdown of protected servers. The UPS will scroll the
front panel indicators sequentially in shutdown mode.
Load Bar Graph
85%
The 5-LED display on the left of the front panel represents the power drawn from the UPS as a percentage of total
67%
50%
capacity. For example, if three LEDs are lit, the load is drawing between 50% and 67% of the UPS's capacity. If all five
33%
LEDs light, thoroughly test your complete system to make sure that the UPS will not become overloaded.
17%
Cold Start
When the UPS is off and there is no utility power, use the cold start feature to apply power to the loads from the UPS's battery.
Press and hold the on/test button until the UPS beeps.
Release the on/test button during the beeps and the loads are powered within 4 seconds.
117 Utility Voltage Bar Graph
109
This UPS has a diagnostic feature that displays the utility voltage. With the UPS plugged into the normal utility power,
101
press and hold the on/test button to see the utility voltage bar graph display. After approximately four seconds the 5-LED
92
display on the right of the front panel shows the utility input voltage. Refer to the figure below for the voltage reading.
84
The display indicates that the voltage is between the displayed value from the list and the next higher value. For example,
with three LEDs lit, the input voltage is between 101 and 109 VAC.
If no LEDs come on and the UPS is plugged into a working AC power outlet, the line voltage is extremely low.
If all five LEDs come on, the line voltage is extremely high and should be checked by an electrician
Note: The UPS starts a self-test as part of this procedure. The self-test does not affect the voltage display.
Note: Cold start is not a normal condition.
The utility voltage bar graph has a margin of error of
5
4%.