4 Maintenance and inspection
4-3 Measuring the backup time
BU5002R/BU3002R/BU3002RH
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4-3-2 Estimated backup time
The backup time varies depending on the capacity of the connected device.
Calculate the total capacity of the connected device and refer to the backup time graph to
use it as a guide of the backup time initial value. (This is the same for inspecting the
battery.)
(1) Convert the total capacity (power consumption) of the connected devices to W (watts).
For the indication of connected devices, check your computer body and the rear of the
display.
There are 3 types of display method: VA (volt-ampere), A (ampere), and W (watt).
Example 1) AC200V, 50/60Hz ,145W
Indication
Value
Example 2) AC200V, 50/60Hz, 1.8A
VA
W = VA × power factor
Example 3) AC200V, 50/60Hz, 150VA
A
W = A × power supply
voltage × power factor
For devices that use VA and A indication, convert the capacity into W. Multiply the value
indicated on devices in the right table for conversion.
(If the power factor is not clear, use “1”. The value of power factor is normally between
0.6 and 1.)
(2) Add the values converted into W to obtain the total capacity of the connected devices.
(3) Calculate the initial value of the backup time for the total capacity of the connected
devices from the graph.
● Backup time graph (this is a graph for the initial value of a new product, with
properties at 25°C.)
If the temperature is lower then the backup time is shorter than the value on the
graph (table) below.
● If the capacity of the connected devices is smaller then the backup time becomes
longer.
