The 10 Best Uninterrupted Power Supplies
This wiki has been updated 33 times since it was first published in April of 2015. It is easy to forget how dependent we are on electricity -- until the lights go out. When they do, computers and networks risk losing valuable data, and A/V equipment can suffer damage. One of these uninterrupted power supplies will provide the battery backup you need to keep your devices running long enough to shut them down safely, with most also offering surge protection, too. When users buy our independently chosen editorial recommendations, we may earn commissions to help fund the Wiki.
February 04, 2021:
Those who work with sensitive data, or in areas where the electrical supply is inconsistent and unreliable, know the importance of owning a UPS system. Whether it's to provide battery backup to a desktop PC, support a multi-unit server rack, or to supply consistent power to counter significant losses in current, or "brownouts", these systems can potentially prevent loss and also damage, thanks to their surge-protection qualities.
The latest review of our ranking introduces two new models, including the Tripp Lite SMART2200NET, which replaces the rack-mountable Tripp Lite 1000RM1U. The former is a tower unit, which is not as compact a solution as its predecessor, but is worthy of inclusion due to its impressive battery capacity, expandable runtime, and its ability to serve six units at once.
Our next addition, the APC BX1500M, is quite different in that it is a compact unit, that is best utilized to provide backup for office spaces. Despite its size, it provides five backup outlets and five surge protection outlets, which should be enough to secure a couple of workstations, and stands upright underneath a desk, creating a small, unobtrusive footprint.
January 06, 2020:
In reorganizing this ranking, we found ourselves torn between two models that were previously both included, feeling that we couldn't justify keeping both around. These were the APC BE550G and the APC BE850M2, each of which has some pretty impressive capabilities for their size and price point, and each of which are targeted to a less professional market than something like the company's APC SMT1500C SmartConnect with its slew of top-tier features. Ultimately, we felt since neither model had active voltage regulation, that it made sense to keep the less powerful, less expensive option. If users need to reach for something in that power range, they're likely to be using devices that could benefit from the protection that active regulation provides.
In the place of that removed APC model, we found another offering from the company, the APC Sine Wave UPS, and it's hard to say enough good things about this model. In a few important ways, it's a slightly more modernized version of the Cyberpower Sinewave UPS, most importantly perhaps in its use of a USB Type-C port, as so many laptops, monitors, and mobile devices are migrating to that standard for power and data.
What Is An Uninterrupted Power Source?
For especially large power needs, a dynamic UPS is appropriate.
An uninterrupted power supply provides backup power when there is a blackout or your main power source goes out for some reason. It differs from an emergency power system, which takes time to activate, in that it kicks in instantly during an outage. If you cannot afford to lose power during a project – like an all-day download – a UPS is your best option to protect against data loss and prevent system interruption. That’s why it’s called uninterrupted because it completely overrides an outage.
There are three main types of uninterrupted power supplies, namely the on-line, the line-interactive, and the standby. An on-line UPS accepts an alternating current input, converts it into direct current to send it through the rechargeable battery, and then turns it back into an alternating current to power the protective equipment. A line-interactive UPS redirects the battery’s DC path from charging mode to supplying mode during an outage. It’s a very intuitive machine that can maintain power reserves during continuous undervoltage or overvoltage situations by selecting the perfect amount of backup power to supply. A standby system (also known as an offline system) is directly powered by a standard AC wall outlet, and it only provides backup power if the main power source fails. Standby UPS systems are the simplest and most popular type for personal computers, offering basic features like surge protection and a backup battery.
For especially large power needs, a dynamic UPS is appropriate. Dynamic models use a synchronous alternator that is connected to the main equipment through a choke. The unit stores energy in a flywheel, and during an outage, an Eddy-current regulator holds onto the power. Recently, technicians developed a fuel cell UPS, which is more environmentally friendly and quiet. It uses hydrogen and a fuel cell as a power source and is ideal for small areas.
Common Causes Of Power Outages
There are several reasons the power goes out ranging from human error to natural disasters. In a strong storm, a tree can fall on a power line, breaking it and cutting off power to an entire neighborhood or town. If you live in an area with extreme weather, always let the city tree trimmers do their mandated work in your yard – they are doing it for your safety, and possibly removing shrubbery that’s too close to a power line. If a storm doesn’t cause a tree to fall, it could send a lightning bolt into a power line, or cause a flood that damages above or below-ground electrical equipment.
Workers can accidentally drill into a power line, or back a tractor over one.
If you live in an area with a lot of wildlife activity, a UPS can be invaluable. An animal can crawl onto a transformer or fuse, causing the equipment to automatically shut down to protect the rest of the system, rendering you powerless. If you live in a remote area, you could be tens of miles away from a building with power, so you need to provide your own.
Construction work on your property or street can cause a power outage. Workers can accidentally drill into a power line, or back a tractor over one. A car crashing into a pole could cause an outage, too. Familiarize yourself with important safety precautions, in case there is ever a loose power line on your street. In addition to having a UPS ready, you should know what to do if you can't regain power for several hours.
The Largest UPS In The World
In Fairbanks, Alaska, where temperatures can drop as low as negative 50 degrees celsius, power outages used to be a common problem. The remote nature of the state means an outage could be very dangerous since the only way for residents to travel to another state is by boat or plane. If communication towers are down, navigating either of these vessels is dangerous. Within Alaska, there are also people living in almost total isolation, so they’re nearly helpless if their power fails. People simply cannot survive if their heater breaks in negative 50-degree weather.
That quarter of an hour gives the system time to retrieve backup generation.
In August 2010, technology group ASEA Brown Boverithe installed the world’s largest UPS in Fairbanks. The system is made up of a converter designed by ABB, and nickel cadmium batteries created by battery manufacturer Saft. The converter turns the batteries’ DC power into AC power, and can produce up to 27 megawatts of power for 15 continuous minutes. That quarter of an hour gives the system time to retrieve backup generation. The system can deliver 46 megawatts of power for an even shorter time frame, but Fairbanks primarily needs it to deliver power just long enough for backup generation to start up.
The UPS can operate in seven different modes, one of which is automatic scheduling, which offers immediate system support if a breaker trips on a transmission line or local generator. It also has a power system stabilizer mode, which works to dampen power system oscillations. In charging mode, a dispatcher controls at what rate megawatts charge the UPS, and when the system can begin charging again after an emergency discharge.