Eaton 5P650IRNG2 UPS 650 VA / 520 W, line-interactive, rackmount, 4 × C13

UPS capacity is quoted in two units. 650 VA is the apparent power, while 520 W is the real power, meaning what the connected devices may draw in total; the power factor is 0.8. When sizing, go by watts and leave headroom: if your router, switch, firewall and a small server together draw well under 520 W, the UPS runs comfortably and the battery lasts longer during an outage. The manufacturer quotes a typical runtime of 7 minutes at half load.

A line-interactive UPS does not switch to battery at every small fluctuation. Automatic voltage regulation smooths out sags and surges without draining the battery, and the unit only goes to battery when the mains fails or the voltage leaves the permitted range. The input operating range is 150–294 V at 47–70 Hz, and the output is held at 200–240 V and 50/60 Hz. The output voltage is a sine wave, just like regular mains power.

The battery is a sealed lead-acid (VRLA) type with two cells, 9 Ah capacity and 6 V voltage. According to the manufacturer it is hot-swappable, so it can be replaced without switching off the UPS or the connected equipment. In a server room this means a battery change needs no planned downtime and no late-night maintenance window. The LCD display on the front panel shows the UPS status right at the rack, with no need to log in anywhere.

The UPS has a USB Type-B port and an RS-232 serial interface, and a USB cable is included. Through them a server or computer is notified when the UPS switches to battery, and power management software can shut the system down cleanly before the battery runs out. The chassis also has a network card slot: with a card installed, the UPS can be monitored and connected equipment shut down over the network, which helps when several servers sit behind one UPS.

The chassis measures 438 × 361 × 43.2 mm and weighs 8.68 kg, and the rack mounting kit is included. The manufacturer quotes a noise level of 35 dB and 97 % efficiency, so the UPS itself wastes little energy and gives off little heat. It is rated for 0–40 °C operating temperature, 0–90 % relative humidity and altitudes up to 3000 m. The unit complies with IEC/EN 62040-1, 62040-2 and 62040-3 as well as UL 1778.

Small businesses whose rack holds a router, switch, firewall and NAS that must ride out a short outage; IT administrators who want to monitor the UPS remotely through a network card later on; and any rack installation with a load under 520 W where a battery change must not mean downtime.