UPS Systems

Add up the actual power draw of everything it will protect, in watts, and choose a UPS whose watt rating is comfortably above that, with the load at no more than about 80 percent. Then pick the runtime: a few minutes is enough for an automatic shutdown, while riding out an outage needs a bigger battery. Send the equipment list and the team will do the sums.

VA is apparent power and watts is real power; the watt rating is lower and is the one that matters for the load. A 1500 VA unit might be rated 1000 or 1350 W depending on the model, so compare the watt figures when choosing.

Line-interactive units are cheaper and suit network cabinets, small servers and branch offices. Online units run the load from the inverter at all times, so the equipment never sees a transfer or a mains disturbance; choose online for production servers and storage.

It depends on the load and the battery. At full rated load most rack units give only a few minutes, which is designed for a clean shutdown rather than continued operation. Lighter loads run longer, and external battery packs extend runtime where it is needed.

Yes. Connected by USB or serial, or through a network management card, the UPS tells the operating system or the virtualisation host that it is on battery, and the shutdown runs on a schedule you set. The network card is the better option where the UPS feeds more than one machine.

Sealed lead-acid batteries typically need replacing every three to five years, sooner in a hot room, and the UPS will warn when they weaken. Lithium models last longer at a higher price. ServerDove can quote replacement batteries for a unit it supplied.