APC Back-UPS BE850G2-UK review

The BE850G2-UK is an 850 VA / 520 W standby UPS with eight UK sockets. It suits desk-side and small home office use: a PC, a router, a switch, perhaps a NAS. The 520 W rating is about three to five times the 100-150 W a NAS, router and switch draw between them. That leaves plenty of headroom for a modest network cabinet.

It is a compact unit. It measures 13 x 36.5 x 12 cm, weighs 4.5 kg and has a 1.83 m cord.

The unit uses standby topology and outputs a stepped approximation to a sinewave. Transfer time is 6 ms typical and 10 ms maximum. Owner reports are positive on the switchover: two independent mentions say it moves to battery quickly and shuts down PCs cleanly.

The stepped waveform is the point to check against your own equipment. The research does not list which devices tolerate it, so check what your kit's manufacturer says before you buy.

There are eight BS 1363A UK sockets. Six are battery-backed with surge protection and two are surge-only. The split is useful: put the router, switch and NAS on the battery-backed sockets, and leave a monitor or speakers on the surge-only pair.

Surge energy is rated at 310 J. The RJ-45 port is dataline surge protection only, listed for 10/100 Base-T. Two USB ports, one Type A at 2.4 A and one Type C, are listed as charging ports.

APC publishes a runtime table:

• 72 minutes at 50 W
• 34.1 minutes at 100 W
• 14.3 minutes at 200 W
• 7.7 minutes at 300 W
• 4.5 minutes at 400 W
• 2.6 minutes at 500 W

No figure is published at half load (260 W). With a 100 W load, the 34.1-minute figure leaves time for a managed shutdown. With heavier loads, runtime falls off quickly. One review says the unit is not suited to high-wattage loads such as heaters or laser printers, and the 500 W figure of 2.6 minutes points the same way.

The battery is a single sealed lead-acid cell. It is user-replaceable, and the RBC17 is sold separately. Expected battery life is 2 to 5 years, and typical recharge time is 16 hours. Budget for a replacement battery rather than a replacement unit when it wears out.

This is the weakest area on paper. The unit ships with PowerChute automatic shutdown software. The research says USB HID compatibility with NAS systems is not verified. That matters if you want Synology, QNAP, TrueNAS or NUT to shut down automatically. Some sources describe the unit being used for network equipment and NAS drives, but the research rates those sources as weak and marketing-adjacent.

One source reports unclear load and sensitivity readings in PowerChute. If you plan to run a NAS, confirm the connection with your NAS vendor or NUT compatibility lists before ordering.

One source calls the audible battery alarm irritating. It is a single report, so treat it as a possibility rather than a pattern.

Warranty details are unresolved. The older manufacturer page lists 2 years on unit and battery and also mentions a 3-year warranty. Retailers and distributors list 3 years. Check the length with the seller at purchase.

The BE850G2-UK has generous socket provision and a clear runtime table. It suits a PC and network gear setup where a clean shutdown is the goal. Its standby topology and stepped sinewave output need checking against your equipment, and unverified NAS USB HID support is a risk for homelab users. Check both before buying.