Uninterruptible power supplies (UPS) review

Beat the blackout blues with these battery backup units.
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05.What to look for

Here’s some key things to look for when shopping for a home UPS:

  • Audible indicators — sounds can draw attention to important conditions. This is useful if the UPS is kept out of sight, like under a desk.
  • Capacity — represented by a VA rating. For example, 550VA. In a power outage the battery life of the UPS will depend on the number and type of devices connected.
  • Circuit breaker switch — to prevent overloading.
  • Communication port protection — surge protection for phone, fax, modem or network
  • Outlet number and type — the number of outlets for battery backup and surge-only will vary with make and model.
  • PC connectivity type — check what type of connection the UPS has for a computer. Modern UPS units will typically use a standard USB connection, but in some cases only come with an older-style serial port (RS232), which is no longer included on most modern PCs, and requires the purchase of a USB-Serial adapter.
  • Power management software — essential for configuring and monitoring the UPS and enabling unattended shutdown of a connected computer in a power outage.
  • Standard outlets — check for outlets that match your computer equipment. Some UPS units have IEC C13/C14 connectors rather than Australian standard domestic 3-pin power plug sockets (AS/NZS3112).
  • Surge protection — not only on the battery backup outlets but also at least one surge-only outlet.
  • Battery type — a user-replaceable battery means you won’t have to send the unit back for service when a new battery is needed. Due to the potentially dangerous voltages involved, however, some UPS units require the battery to be replaced by an authorised technician, for safety reasons.
  • Visual indicators — LEDs on the front or top of the UPS provide information about the system’s major functions.
  • Warranty — we suggest a minimum of two years warranty, ideally.

Which is for you?

There are basically three types of UPS you will find: online, line interactive, and standby. All the units in our test were either line interactive or standby. On the whole line interactive units are the better option, but often cost more.

  • Online (also known as double-conversion), is the most sophisticated type of UPS system and hence the most expensive. It’s often used in large UPS units for industrial applications, rather than domestic systems.
  • Line interactive units provide power conditioning circuitry along with battery backup. They regulate power to an acceptable level, to ‘smooth out’ the power supply in the event of minor power sags without resorting to the battery backup. This makes them a better option in areas where there are frequent power fluctuations.
  • Standby (also called offline) remain in standby mode until the power supply fails, then the battery takes over. They are generally the cheapest of the three types, but don’t provide line conditioning.


  • Blackout: A short- or long-term total loss of mains electricity power.
  • Brownout: A temporary drop in voltage in an electrical power supply.
  • Circuit breaker: An automatically-operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit.
  • Dropout: Momentary loss of electrical power.
  • Overload: In electricity supply, overload refers to a situation where a larger than intended electric current exists through a conductor, leading to excessive generation of heat and the risk of damaging equipment and causing fires.
  • VA: A measure of electrical power. The amount of power in an alternating current (AC) circuit equal to a current flow of one ampere at an electromotive force of one volt. On a UPS the VA rating is the apparent power that a UPS is capable of producing.

Warranty wrangles

Some UPS units come with a ‘connected equipment warranty’. The idea is that if any of your equipment connected to the UPS suffers damage while connected, it’s covered for repair or replacement. Sometimes this type of insurance cover runs into six figures. On the face of it this sounds like a good idea if you want peace of mind, and several of the UPS units we tested came with a connected equipment warranty. For example, the APC BE550-AZ and Belkin F6S600auUSB units provide $150,000 and $100,000 connected equipment protection, respectively.

Read the fine print however, as you may have a hard time collecting the money. In addition to stringent requirements, you may not be covered in particular circumstances or if you’re in Australia you may not be covered at all! The MGE Ellipse 600 and MGE Ellipse Max 850 for example only provide cover if you live in the European Union (EU). As with surge protectors, don’t base a purchasing decision on a connected equipment warranty.


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