APC Back-UPS 850VA
(19 reviews)
Power cut hitting your home solar setup? The APC Back-UPS 850VA keeps a NAS or home server running just long enough for a clean, safe shutdown.
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Characteristics
- Power: 850 VA / 520 W
- Outlets: 8, 6 battery-backed
- Runtime: Up to 9 min at 260 W
- USB ports: 2 (USB-A + USB-C) fast charge
- 8 outlets, fast USB-C, 3-year warranty
Detailed overview: APC BE850G2-UK UPS
On a home solar setup, a mains dropout or a brief glitch on the inverter can interrupt a NAS or home server mid-write, with a real risk of data corruption. The APC Back-UPS 850VA (BE850G2-UK) is built exactly for this: an off-line UPS that switches to battery in a fraction of a second, giving the equipment time to shut down cleanly, or letting a router, a broadband hub or a security camera keep running for a few more minutes.
At 850 VA / 520 W, it comfortably covers a 2 or 4 bay NAS, a small server, a low-draw solar micro-inverter, or several networking devices plugged in at once. Of the 8 outlets, 6 are battery-backed and surge protected, while the remaining 2 offer surge protection only, best kept for less critical peripherals like a printer or a monitor. Two fast USB ports, one Type-A and one Type-C, let you charge a phone or tablet straight from the UPS.
A protected RJ-45 network port rounds out the package: your router or fibre line stays shielded from surges travelling down the cable, a risk that is easy to overlook even when equipment is unplugged from the mains. Runtime varies with load, from around 9 minutes at 260 W down to roughly 2 minutes at full load: plenty for a clean NAS shutdown, not enough to keep working through a long outage.
The unit stays compact (130 x 365 x 120 mm, 4.5 kg) and the battery is user-replaceable, a real advantage over rivals that ship with a sealed cell. Backed by a 3-year warranty from APC/Schneider Electric, with LED status indicators and an audible alarm, the Back-UPS 850VA remains a solid choice for anyone looking to protect a connected home setup without stepping up to a professional-grade UPS.
EAN: 0731304347279
Comparison
Under £150, the APC Back-UPS 850VA (BE850G2-UK) goes head to head with several popular home UPS units in its power range, in searches such as “APC BE850G2 vs Eaton 3S” or “APC Back-UPS 850VA vs CyberPower”. Here is how it stacks up against three of its most compared alternatives: the Eaton 3S 700 FR, one of its closest rivals on price per outlet; the Riello iPlug IPG 800, a compact, budget-friendly alternative; and the CyberPower CP900EPFCLCD, a pure sine wave reference for anyone wanting more headroom.
| Criterion | APC Back-UPS 850VA | Eaton 3S 700 FR | Riello iPlug IPG 800 | CyberPower CP900EPFCLCD |
|---|---|---|---|---|
| Power | 850 VA / 520 W | 700 VA / 420 W | 800 VA / 480 W | 900 VA / 540 W |
| Outlets | 8 (6 battery-backed) | 8 (all UK/EU type) | 6 (Schuko) | 6 |
| USB ports | 2 (USB-A + fast USB-C) | 2 (USB-A 2A) | 1 (data communication only) | Not stated |
| Output waveform | Simulated (off-line) | Simulated (off-line) | Approximated | Pure sine wave (PFC) |
| Warranty | 3 years | 2 years | Not stated | Not stated |
| Observed price | £145.50 | ≈ £96 | ≈ £83 to £103 | ≈ £170 |
Overall, the APC Back-UPS 850VA remains the most well-rounded pick in its category: it delivers the best power per pound against both the Eaton and the Riello, while staying well below the CyberPower's pure sine wave price. The Eaton 3S 700 FR is a credible alternative if a 2-year warranty is enough, and the Riello iPlug wins on entry price, but neither offers a fast USB-C port. The CyberPower CP900EPFCLCD only really makes sense for equipment that specifically needs a pure sine waveform.
Related video
Video: APC Back-UPS ES BE850G2-UK Review: Is 850VA Power Backup Worth It? - Published on 30/04/2025
Our tester's review: Dawid Lojewski
After a few weeks running behind our office NAS, wired into the same circuit as our solar setup, this APC just gets on with the job quietly. During a ten-second mains dropout, the NAS didn't even blink: instant switchover, no reboot. On a longer cut, the audible alarm gives plenty of warning to trigger a clean shutdown before the battery runs flat. The 8 outlets are well laid out, and being able to plug a USB-C cable straight into the UPS to top up a phone during an outage is more useful than it sounds. The one real downside: runtime drops fast as you approach full load, so don't expect to keep working through a long cut, just to shut everything down safely. For the price, the 3-year warranty is a genuine edge over most rivals.
Frequently asked questions: APC BE850G2-UK UPS
Runtime depends on the connected load: around 9 minutes at 260 W, but only 2 to 3 minutes at full load (520 W). Enough to trigger a clean shutdown of a NAS or server, not to keep working for long.
Yes, that is a typical use case: if the mains drops or the solar inverter faults, the BE850G2-UK's battery kicks in within a fraction of a second, giving the NAS time to shut down cleanly and avoid data corruption.
The first 6 outlets are both surge protected and battery-backed during a cut. The remaining 2 only offer surge protection, with no battery backup, so keep them for non-critical devices.
Yes, the battery is user-replaceable without tools, a genuine advantage for extending the UPS's lifespan beyond the usual 3 to 5 years of a sealed lead-acid battery.
No, this off-line model delivers a simulated waveform on battery power, which is more than enough for a NAS, a router, a broadband hub or a monitor. Only sensitive equipment (hybrid solar inverters, high-end audio gear) really needs a pure sine wave.
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Published on 04/09/2026