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APC Back-UPS BX750MI 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 BX750MI at 5.2/10.

The APC Back-UPS BX750MI leads on topology and waveform, capacity and runtime and battery.

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

The biggest difference is NAS and server integration, where the Eaton 3S Gen2 UPS 3S550B scores 7/10 to the APC Back-UPS BX750MI's 4/10.

APC Back-UPS BX750MI

APC Back-UPS BX750MI

5.2/10verdict: wait for deal

The APC Back-UPS BX750MI is for people protecting a small NAS, router and switch who already own IEC C14 power leads. It suits a buyer who values line-interactive protection and decent battery runtime more than a pure sine wave output. It is less suited to anyone who needs confirmed automatic NAS shutdown or UK 13A sockets on the unit.

Typically about £84.80 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 BX750MIEaton 3S Gen2 UPS 3S550B
Topology and waveform25%5/104/10
NAS and server integration25%4/107/10
Capacity20%7/106/10
Runtime and battery15%6/105/10
UK outlets and build15%4/106/10
Overall5.2/105.6/10

Specifications

SpecAPC Back-UPS BX750MIEaton 3S Gen2 UPS 3S550B
Capacity (VA / W)750 VA / 410 W550 VA / 330 W
TopologyLine-interactiveOffline/Standby
Output waveformStepped approximation to a sine wave, not pure sinenot listed
OutletsFour IEC 60320 C13 outlets, all battery-backed6 UK outlets: 3 with battery backup and surge protection, 3 surge-only
Runtime at half load8.5 minutes at half load (full load 1 minute), retailer spec table, not confirmed on APC pagenot listed
USB / network managementUSB port listed; USB HID protocol and Synology/QNAP/TrueNAS support not confirmed on an APC pageUSB port (HID-compliant), Eaton UPS Companion software, auto shutdown function; no Ethernet or network card
BatterySealed lead-acid, 12 V nominal; recharge time 8 hours; expected life 3-5 years; user replaceability not confirmed on an APC page12 V / 5 Ah sealed VRLA, one battery, user replaceable

Strengths and weaknesses

APC Back-UPS BX750MI

  • + Line-interactive topology with 410 W capacity
  • + Four IEC outlets, all battery-backed
  • + Owners praise runtime and power-cut performance
  • − Stepped sine output, not pure sine
  • − USB HID and NAS support not confirmed by APC
  • − Owners report heat, smell, build and failure issues

Skip it if:

  • Buyers who need confirmed automatic shutdown with Synology, QNAP or TrueNAS
  • Anyone who wants UK 13A sockets on the unit
  • Users whose equipment needs a pure sine wave output
Read the full APC Back-UPS BX750MI 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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