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APC Back-UPS BE850G2-UK vs Eaton 3S Gen2 UPS 3S550B

Researched, not hands-on tested.How we review ›

all judged against UPS units at a similar price

The Eaton 3S Gen2 UPS 3S550B scores 5.6/10 overall, ahead of the APC Back-UPS BE850G2-UK at 5.4/10.

The APC Back-UPS BE850G2-UK leads on capacity, runtime and battery and UK outlets and build.

The Eaton 3S Gen2 UPS 3S550B leads on NAS and server integration.

They score the same on topology and waveform.

The biggest difference is NAS and server integration, where the Eaton 3S Gen2 UPS 3S550B scores 7/10 to the APC Back-UPS BE850G2-UK's 4/10.

APC Back-UPS BE850G2-UK

APC Back-UPS BE850G2-UK

5.4/10verdict: wait for deal

The APC Back-UPS BE850G2-UK suits a home office or small desk setup that needs battery backup for a PC, router and switch. It offers six battery-backed UK sockets and a published runtime table. Buyers who need confirmed NAS shutdown support or a pure sine output should check those points first.

Typically about £120 in the UK when we researched itCheck price at Amazon UK (opens in a new tab, affiliate link)

Affiliate link. As an Amazon Associate I earn from qualifying purchases. Details

Eaton 3S Gen2 UPS 3S550B

5.6/10verdict: wait for deal

The Eaton 3S Gen2 3S550B is a small standby UPS for a home desk or a compact homelab. It suits someone protecting a NAS, router and switch who wants USB-triggered shutdown and a user-replaceable battery. It doesn't suit anyone who needs a confirmed waveform, a published runtime or network management.

Typically about £83.99 in the UK when we researched itCheck price at Amazon UK (opens in a new tab, affiliate link)

Affiliate link. As an Amazon Associate I earn from qualifying purchases. Details

Scores, criterion by criterion

CriterionWeightAPC Back-UPS BE850G2-UKEaton 3S Gen2 UPS 3S550B
Topology and waveform25%4/104/10
NAS and server integration25%4/107/10
Capacity20%7/106/10
Runtime and battery15%6/105/10
UK outlets and build15%7/106/10
Overall5.4/105.6/10

Specifications

SpecAPC Back-UPS BE850G2-UKEaton 3S Gen2 UPS 3S550B
Capacity (VA / W)850 VA / 520 W550 VA / 330 W
TopologyStandbyOffline/Standby
Output waveformStepped approximation to a sinewavenot listed
Outlets8 total: 6 battery-backed with surge protection and 2 surge-only, all BS 1363A UK sockets6 UK outlets: 3 with battery backup and surge protection, 3 surge-only
Runtime at half load72 min at 50 W, 34.1 min at 100 W, 14.3 min at 200 W, 7.7 min at 300 W, 4.5 min at 400 W, 2.6 min at 500 W; no figure published at half load (260 W)not listed
USB / network managementTwo USB charging ports (Type A 2.4 A and Type C); ships with PowerChute automatic shutdown software; RJ-45 port is dataline surge protection only; USB HID compatibility with NAS systems not verifiedUSB port (HID-compliant), Eaton UPS Companion software, auto shutdown function; no Ethernet or network card
BatteryOne sealed lead-acid battery, user-replaceable (RBC17 sold separately); expected life 2 to 5 years; typical recharge 16 hours12 V / 5 Ah sealed VRLA, one battery, user replaceable

Strengths and weaknesses

APC Back-UPS BE850G2-UK

  • + Six battery-backed BS 1363A sockets plus two surge-only
  • + Runtime table published from 50 W to 500 W
  • + User-replaceable battery, with RBC17 sold separately
  • − Standby topology with stepped sinewave output
  • − USB HID compatibility with NAS systems not verified
  • − Warranty length conflicts between manufacturer and retailers

Skip it if:

  • Homelabbers who need confirmed automatic shutdown with Synology, QNAP, TrueNAS or NUT.
  • Anyone powering heaters, laser printers or other high-wattage loads.
  • Buyers who want a pure sinewave output from their UPS.
Read the full APC Back-UPS BE850G2-UK review ›

Eaton 3S Gen2 UPS 3S550B

  • + USB port is HID-compliant, with automatic shutdown support
  • + Battery is a single user-replaceable sealed unit
  • + Six UK outlets, three of them with battery backup
  • − Offline/standby topology; Gen2 waveform not confirmed by Eaton
  • − Half-load runtime isn't published by the manufacturer
  • − No Ethernet port or network card

Skip it if:

  • Buyers who need a confirmed pure sine wave output
  • Anyone needing network-card monitoring for several servers
  • Users who need a published runtime figure before buying
Read the full Eaton 3S Gen2 UPS 3S550B review ›

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