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Reasons a Smart-UPS Will Transfer to Battery


When will my UPS switch to battery?

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All models, All Serial Numbers


Normal Operation.


Smart-UPS protect data by supplying network-grade battery backup when power fails. Computer hardware is protected and system life extended through superior full-time multistage surge suppression and noise filtering. The Smart-UPS can switch to on-battery operation as a result of power disturbances or software initiated commands. There is a common misperception that a Smart-UPS will use its battery based only on voltage fluctuations. The following list provides the possible causes for a Smart-UPS switching to battery operation, along with a brief definition of each.

No Voltage (Blackout): A total loss of utility power.

Low Voltage (Brownout): A decrease in voltage levels. Sometimes this is not visually noticeable.

High Voltage (Over Voltage): A surge is a short-term increase in voltage.
A spike is an instantaneous dramatic increase in voltage.

Total Harmonic Distortion (THD): Periodic distortion of the sine wave. Harmonics add to the fundamental frequency in magnitude.

Change in Voltage (dv/dt): Rapidly changing voltage. If the voltage increases or decreases rapidly, the Smart-UPS will transfer to battery because the Smart-UPS does not know how high or how low the voltage will go.

Frequency Changes (Hz): Deviation from the nominal 60Hz in North America.

Computer Interface/Accessory Issues

A Smart-UPS has a microprocessor inside which allows communication with APC's PowerChute software, APC Accessories, and other native UPS shutdown programs for various operating systems. Interaction with these products could cause a Smart-UPS to operate on battery. A Self-Test or Runtime Calibration can be initiated through a graphical user interface, command prompt, or even when there is a communication problem.

Before concluding that the Smart-UPS is malfunctioning merely because it is operating on battery, be sure to consider all of the above possibilities.

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