Notes on PowerWalker VI 500 R1U UPS

I’ve always wanted a rack mount UPS for all of our homelab gear, and PowerWalker VI 500 was pretty much the cheapest option at EUR 192 at the time. Here are my notes and observations after having used it for more than a year to power a QNAP TS-435XeU server.

PowerWalker VI 500 R1U UPS
  • Has only USB type B connection for management.
  • Is recognized by macOS and QNAP operating systems as UPS when connected over USB.
  • Relies on PowerMaster+ management software for configuration.
  • Has four IEC C13 output sockets.
  • Uses two 6V/7Ah batteries which gives it a theoretical maximum capacity of 84Wh.
  • Has audible transformer hissing when not loaded but is completely fan-less.

Power Consumption

PowerWalker VI 500 R1U drawing 15W unloaded (during 6-8PM) and practically the same when powering a 30W server (during 10-11PM) when fully charged.

The unit draws an additional 15W when powering a 30W NAS (and connected to the mains) which explains why it gets pretty warm (still comfortable to touch). This is a pretty significant overhead for DC-based systems like routers and mini PC servers.

The specification mentions 95% efficiency under full load when connected to the mains and 78% efficiency when powered from the battery (also under full load) with a 0.60 power factor. The official full-load (300W) backup time is 0.8 minutes or 10.3 minutes for the half-load (150W).

After almost exactly a year of this kind of usage, the batteries were completely depleted and wouldn’t last even a few seconds during a blackout — dropping to 10V as soon as the mains power supply was removed.

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