Deliesn Portable Power Station 
What’s an offline UPS? What’s the difference between offline UPS and online UPS? Many people may be confused about the different types of UPS. However, you will BETTER understand the concept after learning the different types of UPS topologies. In this article, we will show you the definition，working principle, block diagram and other details of offline ups.
Deliesn DS500/DS1000/DS1500/DS2000 series products produced by our company are mainly backup UPS, the difference is pure sine wave inverter, which has all the functions of energy storage power, and supports both outdoor and indoor use. Working hours are up to several hours. The power of the battery pack is very large, mainly 1000WH/1500WH/2000WH, which can be used by the machine for a long time.
Offline UPS Definition
Offline UPS, sometimes described as standby power supply (SPS) are systems where the load is fed directly from the raw mains during normal operations instead of the inverter outputs. 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.
Working principle
Look at the offline UPS diagram below，you will understand why people also call it a “backup” or stand-by UPS.
Offline UPS: Usually in the battery charging state, in the event of a power failure, the inverter switches to the working state urgently, and converts the DC power provided by the battery into a stable AC output, so the backup UPS is also called an offline UPS. The advantages of the backup UPS power supply are: high operating efficiency, low noise, and relatively cheap price. It is mainly suitable for occasions where the mains fluctuation is not large and the quality of power supply is not high, and it is more suitable for home use. However, this UPS has a switching time problem, so it is not suitable for use in places where critical power supply cannot be interrupted. However, this switching time is actually very short, generally between 2 and 10 milliseconds, and the switching power supply of the computer itself should be able to maintain about 10 milliseconds when the power is turned off, so the personal computer system generally does not appear due to this switching time. question. The backup UPS can only last for a few minutes to dozens of minutes, mainly to give you time to back up data and end the work at hand as soon as possible, and its price is also low. For computer applications that are not too critical, such as individual home users, a low-power backup UPS can be configured.
Difference between online UPS and offline UPS
The key difference between Online UPS and Offline UPS lies in their work. An Online UPS supplies the AC power through a rectifier and inverter circuit even when the AC mains power is available.
Advantages of offline UPS
1.Compared with online UPS price，offline UPS’s are cheaper.
2.High efficiency, making it the most commonly used for providing power supply for personal computers and is also used for office supply.
3.Smaller size. The stand by UPS is available in small and compact sizes which is important when there is no big space available. Its compact size makes the stand by UPS’s first choice when it comes to supplying computers in-home use.
In a word, you can buy an offline ups to protect your equitment from power failure, sags and surges in a low price, but if you want a UPS which can offers total power protection, you should get an online ups rather than offline.
Online UPS keeps its inverter in working condition. It first converts external alternating current into direct current through the circuit, and then converts the direct current into high-quality sine wave alternating current through a high-quality inverter and outputs it to the computer. The main function of the online UPS in the power supply situation is to stabilize the voltage and prevent the interference of radio waves; in the event of a power failure, the backup DC power supply (battery bank) is used to supply power to the inverter. Since the inverter is always working, there is no switching time problem, which is suitable for occasions with strict requirements on power supply. One of the advantages of online UPS different from backup type is that the power supply lasts for a long time, usually a few hours, but also as large as more than ten hours. Its main function is to allow you to work as usual in the event of a power outage. Obviously , due to its special functions, the price is obviously a lot more expensive. This kind of online UPS is more suitable for the computer, transportation, banking, securities, communication, medical, industrial control and other industries, because the computer in these fields generally does not allow the phenomenon of power failure.