Difference between Online UPS and Offline UPS

UPS is the IT world and the short form of the uninterrupted power supply. These UPS is categorized into two types. One is online UPS and the other is offline UPS. In this article, we are going to discuss the main key difference between online UPS and offline UPS to better understand this topic.

What is Online UPS?

The online UPS consists of a rectifier, battery, and inverter in-line with AC mains and load. The AC power supplied to the online UPS is fed first to the rectifier circuit, then it will convert it into the DC power. The DC power is used to charge the battery and this DC power is supplied to the inverter and then it is supplied to load.

What are offline UPS?

The offline UPS directly supplies the AC power to the device connected to the load. In case of power failure, the offline UPS changes the position of the transfer switch, and then it connects the load to the battery backup path.

Difference between online UPS and offline UPS:

  • The online UPS supplies the AC power through a rectifier and inverter circuit even when the AC mains power is available, While offline UPS directly supply the AC mains power to the load circuit when the power supply is available.
  • The price of the online UPS is more than the offline UPS.
  • The efficiency of the offline UPS is more than the efficiency of the online UPS.
  • Online UPS and offline UPS is that the inverter in online UPS is ON all the time while inverter in offline UPS is on only when the power supply is unavailable.
  • The online UPS use it when a UPS for a longer duration of time and the main power supply fluctuates drastically, while in offline UPS use it when you are much concerned about the cost and when you wish a lower operating temperature.
  • The reliability when you use the UPS for a longer time, it renders unreliable service, while Offline UPS renders reliable service because of fewer parts used and the lesser operating temperature.
  • There is in the frequent high voltage fluctuation, where we need to install online UPS, while the offline UPS use it when you are much concerned about the cost and when you wish the use lower operating temperature
  • The transfer time is the key term that differentiates online UPS and offline UPS. The transfer time in the case of online UPS is zero as there is no switching between the inverter rectifier path and the mains supply path. While the offline UPS posses a transfer time of about 5ms.
  • Online UPS uses its battery throughout the time when the electronics device is in use. Therefore the battery is always used here. While the offline UPS is never using the battery until there is a power failure. Therefore the battery is rarely used.
  • High performance of online UPS while low performance in offline UPS.
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