FSP ST 850 Tower 850VA 510W Line-Interactive UPS with RJ45 Protection and 4 Schuko Outlets

With a real power output of 510 W and a simulated sine wave on battery, the FSP ST 850 keeps your critical devices running through outages without a hitch. Its line-interactive topology automatically corrects voltage fluctuations, while the 170–280 V input range handles even the most unstable mains. Four Schuko sockets and RJ45 data line protection make it a complete power shield for your workstation or small office.

Overview

The FSP ST 850 is a tower UPS built for dependable backup power. It delivers 850 VA / 510 W, enough for a PC, monitor, router, and other essentials. The simulated sine wave output ensures compatibility with most power supplies, and the fast 2–6 ms transfer time means your equipment never notices the switch to battery. A USB port allows monitoring and unattended shutdown via software, while audible alarms keep you informed of battery mode, low battery, overload, and fault conditions.

What stands out

• Line-interactive AVR stabilizes voltage without switching to battery, extending battery life.
• Four Schuko outlets provide ample connectivity for your devices.
• RJ45 surge protection guards network lines from spikes and surges.
• User-replaceable 12V/9Ah sealed lead-acid battery recharges to 90% in 4–6 hours.
• Tower form factor fits neatly beside or under a desk.

Technical details

• Topology: Line-Interactive
• Power capacity: 850 VA / 510 W
• Input voltage: 230 V AC (range 170–280 V)
• Output voltage: 230 V AC
• Output waveform (battery mode): Simulated sine wave
• Transfer time: 2–6 ms
• Outlets: 4 x Schuko (CEE 7/4)
• Data line protection: RJ45 in/out
• Communication: USB Type-B
• Battery: 1 x 12V / 9Ah sealed lead acid
• Recharge time: 4–6 hours to 90%
• Audible alarms: Battery mode, low battery, overload, fault
• Surge protection: Yes

Our verdict

The FSP ST 850 is a no-nonsense UPS that covers the essentials: solid power, line-interactive protection, and network surge defense. It’s an ideal choice for home offices and small businesses that need reliable backup without complexity.