Uninterruptible power supplies (UPS) keep computers, network equipment and servers running when the mains fails or the voltage fluctuates. Our range has over 1,000 models: line-interactive, online, standby and rack-mounted UPS units, plus batteries and accessories.
Leading makers include APC, EATON, CyberPower and BlueWalker. The choice suits home offices, small businesses and server rooms.
How to choose a UPS
Power rating. A UPS is rated in volt-amperes (VA) and watts (W), and the watts figure is the one that matters most. Add up the power draw of everything you plan to connect and leave a margin of at least 20-30%, so the unit is not running at its limit.
UPS type. A standby (offline) UPS is the simplest: it switches to the battery only when the mains voltage drops. A line-interactive model also corrects voltage fluctuations, which suits offices and network equipment. An online UPS powers the load through an inverter all the time with no switchover, so it is the usual choice for servers and sensitive equipment.
Runtime. This depends on battery capacity and the load. Most UPS units are meant to give you time to shut a computer down safely, not to run it for hours. If you need longer, choose a model that accepts extra battery packs.
Output waveform. Some cheaper units supply a simulated sine wave when running on battery. Certain computer and server power supplies with active PFC may not work well with it, so in that case choose a model with a pure sine wave.
Form factor and connections. Decide between a tower unit and a rack-mounted one for a 19-inch cabinet. Check that there are enough Schuko or IEC C13 outlets, and whether the UPS connects by USB or network so the computer can shut down automatically.
Brands in our range
- APC: a Schneider Electric brand known for its Back-UPS and Smart-UPS series, which run from home offices up to server rooms.
- EATON: a manufacturer known for online UPS systems and the Ellipse line-interactive series.
- EATON POWERWARE: the former Powerware brand, taken over by Eaton, so these models are mostly professional online systems.
- CyberPower: offers many line-interactive models with a pure sine wave output and an LCD display.
- BlueWalker and PowerWalker: brands of the same German group, covering all the main UPS types.
- Vertiv: a data centre infrastructure manufacturer, formerly Emerson Network Power (Liebert).
Also in our range: Qoltec, Conceptronic, Roline, Online USV Systeme and Tecnoware.
The category includes line-interactive UPS, rack-mounted UPS, online UPS and standby (offline) UPS, as well as UPS batteries and a small selection of UPS accessories.
UPS frequently asked questions
What size of UPS do I need for a computer?
Choose a UPS whose power rating in watts exceeds the total load by about 20-30%. Add up the draw of the computer, monitor and any other connected devices, because the VA figure alone can be misleading. A gaming PC with a powerful graphics card needs considerably more than a basic office computer.
What is the difference between a line-interactive and an online UPS?
A line-interactive UPS feeds equipment directly from the mains and corrects the voltage, switching to the battery within a very short moment when power fails. An online UPS powers the equipment through an inverter all the time, so there is no switchover. Online models cost more and are intended for servers and sensitive equipment.
How long will a UPS keep a computer running?
Usually a few minutes to a few dozen minutes, but the exact time depends on the battery capacity and the connected load. The lighter the load, the longer the UPS lasts. For longer runtimes, look for models that accept additional battery packs.
When does a UPS battery need replacing?
Typically every few years, because lead-acid batteries lose capacity over time. If the UPS reports a battery fault or lasts much less than it used to, it is time to replace it. Suitable replacements can be found in the UPS batteries and accumulators subcategory.
