Uninterruptible power supplies (UPS) review

Beat the blackout blues with these battery backup units.
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04.Our findings

Our tests prove that size isn’t everything with a UPS. Although the largest capacity unit in the test — the 1500VA Powertech MP5206 — finished at the top of the overall rankings, it shared that position with the equal-scored 1000VA Opti ES1000C. Close behind was the 850VA MGE Ellipse Max 850, followed by the 1200VA Power Shield PSD1200. In the Under 700VA category, the 500VA Eaton Powerware 3105 UPS took first place, just ahead of two 650VA units, the Power Shield PSD650 and Upsonic PROffice 650. The Eaton Powerware 3105 also scored very highly for ease of use, placing second-highest of all the UPS units, just behind the Belkin F6S600auUSB.

Running cost

As you might expect, the most powerful UPS in our test was also the most expensive to run. Being a battery backup system, a UPS is designed to run continuously all year round. The annual running cost of the 1500VA Powertech MP5206 was calculated at $38.30, based on the usage scenario of 24hr/day, at 17c per kilowatt hour (kWh). While not in itself a huge cost, it’s more than nine times the cost of the cheapest-to-run UPS unit in our test, the 700VA APC BE700-AZ, at only $4 annually.

Ease of use

Three UPS systems were notable for their excellent ease of use scores: the Belkin F6S600auUSB, Eaton Powerware 3105 and the Opti ES1000C. All three UPS systems included helpful power management software that offered many configuration options. Easy configuration and use of power management software is vital to getting the most out of a home UPS. Particularly important is the software fully support the operating system used on your PC (whether Windows XP or Vista, Mac OS X or Linux). This is essential to the software’s ability to successfully shut the PC down without loss of data when mains power is interrupted.

Setting up

There are two parts to setting up most modern home UPS systems — the hardware and the software. Neither is particularly difficult and can be done by just about anybody, but it’s important to read the instructions that come with each unit.

Note that because you are dealing with power supply devices it is especially important to read the safety instructions. Safety considerations include heeding the manufacturer’s guidelines for the operating environment, and connnecting all devices directly (for example, not plugging the UPS into a power board or extension lead, and not plugging a power board or extension lead into the UPS).

Once the hardware is set up, install any power management software that came with the UPS onto your PC. Do this first, before connecting the USB (or serial) communication cable between the two devices. This will provide the PC with the software drivers needed for it to recognise and use the UPS.

Once the software is installed and the communication cable attached, configure the power management software to suit your needs, or simply accept the default settings.


UPS systems also offer protection from power surges, in addition to battery backup, and most have at least one additional outlet that provides surge protection only. This is ideal for protecting a device such as a printer. See also our test on surge protectors.

In addition to power outlet protection, several UPS systems in this test also include protected connections for data lines (phone, fax, modem and Ethernet network sockets). If you want to include protection for communication ports, check for these features before buying.

All the UPS systems in this test have a replaceable lead-acid type battery. As such, it is heavy, but provides the power needed to keep your PC going when the mains power goes out. It’s important to note whether the battery is user-replaceable, as this can save you time and money when the old one is ready to give up the ghost. The power management software should indicate when the battery isn’t able to hold a sufficient charge and needs replacing.

Many UPS systems will also provide protection against electrical overload. This can take two forms — circuit breaker or fuse — but both provide the same type of over-current protection. If the device becomes overloaded, the circuit breaker switch will trip, requiring a reset, or the fuse will blow, requiring replacement.

Size isn’t everything

The size of the UPS you need depends on the equipment you need to power. Note that a UPS is not designed to power your system so you can keep on working through a blackout, but just to give you the precious minutes needed to save your work and shut down. Our testing showed that size (VA rating) of a UPS is not strictly the best indicator of how much backup power they will give you (see table). Our battery results varied from around four minutes to over 40 minutes, but there wasn’t a strict correlation between battery time and the power rating of the UPS.

As a general rule, if you have similar configuration to our test system (see How we tested ) — a single PC, monitor, and extra peripheral or two — you can generally get away with looking at a unit rated around 650VA or less, which should provide enough time to save your work and properly shut down your PC in the event of a power blackout.

If you want maximum battery powered uptime regardless of cost, the Powertech MP5206 is the pick of the bunch with over 40 minutes on our test system. Both it and the Opti ES1000C had an excellent overall score. The MGE Ellipse Max 850 provides a better value equation however, with a better balance of power and cost. Among the smaller UPS units the Eaton Powerware 3105 and Upsonic PROffice 650 are good performing standby units and great value. The Power Shield Defender PSD650 costs a little more but is a line interactive UPS, while the MGE Ellipse 600 is a standby unit, but gave the longest battery life of the smaller category.

Don’t be shocked!

Even though domestic UPS units are designed for use around the home, it’s important to remember they are a power storage device and safe handling procedures should have priority — as one of our testers learned. The tester unplugged the charged UPS from the wall without turning it off first, and when he touched the metal chassis it gave him a small shock. We recommend that a UPS not be moved when it is powered. If it needs to be moved, always ensure it is turned off first.


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