• The Shocking Truth about UPS Systems

Power outages aren't common, but when they happen, they're a huge irritation. Most of us have had the sinking feeling where the lights go out. A power cut can disconnect a voice or video call, take down our computers in the middle of a file edit, or at the very least interrupt our web browsing. An uninterruptible power supply (UPS) can keep your small business environment running for enough time until the power comes back up. Here's how to choose one.

Watts up?

One of the key features in any UPS is capacity. This is the wattage that it can provide to the equipment on your network. If your endpoints are all laptops with their own batteries, then your necessary capacity will drop significantly, especially if you're able to switch from external monitors to the laptops' own screens. Desktop machines are a different story, as are telephone handsets (including VoIP handsets that draw power over Ethernet).

Don't forget what's in your server room. The UPS must support any server equipment, along with the router that connects you to the internet and your switches and storage arrays, at least long enough to power down gracefully.

How long to wait before powering down is another key factor, and that also affects capacity. Budget for at least enough time to power down your equipment, but consider UPS arrangements that let you keep working for a minimum period to avoid business disruption. For this, refer to the manufacturer's online UPS selector tool. Most of them will let you enter your wattage requirements along with an expected run time.

Different types of UPS

The other variable when choosing a UPS is the type. You can choose from standby, line-interactive, and online models. A standby model does nothing until the power goes out. At that point, it switches over the battery, which takes a few milliseconds.

This is the most basic scenario, but it won't protect you against power surges (when power jumps, perhaps due to a lightning strike), sags (when something else that takes a lot of electrical power starts up), or brownouts (when the local utility lowers power to your area to cope with supply-side stresses). For that, you'll need a line interactive model that automatically regulates the voltage to provide clean power, drawing on the battery where necessary to make up any shortfall.

The premium online UPS filters the power through the battery system, providing all the regulation features of a line-interactive model but with no lag between the power fluctuating and the battery kicking in. Choose this for the highest reliability of all, but expect to pay a premium.

Not all power is equal

Consider the kind of power that the unit provides. Electrical currents travel in an undulating wave known as a sine wave, which the UPS must mimic. Some of them use a modified sine wave inverter that approximates it with a step-like shape (imagine replacing a hill with stairs).

A simulated sine wave can be tough on more sensitive equipment, especially if it uses a feature called active power factor correction (PFC). Choosing real sine wave technology in your UPS guarantees a gentler power supply that could extend the life of your equipment and avoid potential outages with active PFC power supplies.

Other features to look at include the number of battery-backed outlets (some UPS devices provide surge-protected outlets but only a subset of them are connected to the battery). Intelligent battery management will help extend the life of the battery, while some will let you replace the batteries or expand the unit with more batteries for extra run time. You can also get models with building wiring fault indicators, LED screens that display more information, and automatic battery health checks.

Start adding in these features and boosting your capacity and you'll soon find UPS costs escalating. One way to keep the cost down is to rely heavily on your battery-powered laptops while focusing on keeping your network equipment running. For a branch office with a relatively small server, or no server at all if you're relying on the cloud, you should be able to cover all your needs without breaking the bank.