What type of UPS should I choose?
There are three main types of UPS systems: Offline, Line Interactive and Online.
Offline (Standby)
An Offline UPS (also referred to as Standby or Voltage and Frequency Dependent) is the most rudimentary and inexpensive form of a UPS. An Offline UPS is suitable for protecting non-critical devices such as PCs, peripherals and office equipment, or home entertainment gadgets such as TVs and games consoles against power outages. Fundamentally, this type of UPS will feed power directly from the mains to the power supply of the electrical device until a power outage. Once the power goes out, the UPS will switch to using its internal battery to power the attached equipment.
The biggest disadvantage of this type of power supply is that it waits until it senses a loss of power before it automatically turns on the battery. This could cause the equipment connected to the power supply to stop working.
Unfortunately, most Offline UPS systems do not have the necessary features to suppress surges and prevent the equipment from getting damaged.
Line Interactive
A Line Interactive UPS (also referred to as Voltage Independent) offers enhanced protection compared to an Offline UPS. In a Line Interactive UPS, the power from the mains flows into an Inverter/Converter in the UPS. The power is then split into both AC and DC current. The DC charges the battery of the UPS and the AC flows to the power supply of the equipment. When power is lost to the mains, the equipment gets all its power from the battery in the UPS.
A Line Interactive UPS still has transfer time when power is lost, however, it is a faster response than in Offline models. Furthermore, a Line Interactive UPS will filter the AC coming from the mains through the inverter and smooth out any spikes in mains power that could damage your computer.
Online
An Online UPS (often called a “Double Conversion UPS”) offers a premium power protection demanded by critical and sensitive equipment. In an Online UPS, the power comes from the battery of the UPS and the power from the mains is constantly recharging the battery. It is like using a laptop while it is plugged in. If the power goes out, it will continue to run until the battery dies.
An advantage of using an Online UPS is that there is no transfer time should power be lost. Additionally and perhaps even more importantly, by having all the mains power going through the battery, there is another level of protection from any surges or drops in voltage. Surges and voltage drops can wreak havoc on electrical equipment and computer systems, potentially causing damage.
Online UPSs are generally only available with a large output power capacity. While they can be more expensive than Offline or Line Interactive UPSs, they can provide considerable energy savings for large units, as well as more substantial protection overall.
