I've bought a brand new 1200VA Offline UPS, but the problem is my UPS brand doesn't provide the information about charging time. So, I want to know how much time it takes to charge a 1200VA UPS? Also, do I need to keep the UPS connected with power after shutting down my computer?
1 Answer
An offline UPS is a Standby UPS that transfers the load (UPS side) to the AC Inverter in around 5 ms.
Offline UPS - also referred to as VFD (Voltage and Frequency Dependent) or Standby UPS - offer the most basic level of power protection.
When mains supply is present, the UPS output is supplied via a built-in EMI/RFI filter which provides the load with protection from spikes and transients by clamping peak voltage to pre-defined levels.
When the mains supply fails or fluctuates outside of the UPS's operating window, a relay connects the load to the inverter output (resulting in a 4-8ms transfer time). In normal operation, with mains supply present, both output voltage and frequency will track the input voltage and frequency respectively.
Even so, it is best to keep the external AC always connected so the battery can be charged as necessary and so you are ready for a power failure.
In terms of charging time, my own APC 750 true UPS unit charges from low (4 hour power failure and output too low to keep the modem going) in about 3 or 4 hours, 2 hours in most cases for a shorter power failure.
Your 1200 VA unit would charge in a similar time frame.
