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How long will a UPS run my equipment?

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People keeping a desk, modem, and monitor up through a short outage. The decision this page isolates is narrow on purpose: estimate watt-hours and a va floor from office load and desired runtime. Starting load and runtime both have to clear the published rating, not just the running watts.

Office load and runtime

Estimated battery energy

118 Wh

Continuous load
200 W
Planning VA floor
286 VA

Compare UPS units at or above 286 VA whose published runtime chart covers 200 W.

Example products for How long will a UPS run my equipment?

Real products that fit this planning category. Specs come from the manufacturer’s product page. These are examples, not rankings.

Check ups examples on Amazon

Compare the official examples

The table below is a side-by-side of the official examples on this page. Columns are published facts—maker, planning class, and notes taken from the official page—not scores. APC Back-UPS Pro BR1500MS2, CyberPower CP1500PFCLCD, and EcoFlow RIVER 2 are included so you can see how classes differ, then open the official page for the current specification.

Published facts for the example products on this page. Not a ranking.
ExampleMakerPlanning classesPublished notes
APC Back-UPS Pro BR1500MS2APCUps1500 VA; 900 W
CyberPower CP1500PFCLCDCyberPowerUps1500 VA; PFC compatible
EcoFlow RIVER 2EcoFlowUps256 Wh; EPS mode

What to verify before you buy

Measurement notes

Measure: Add the running watts of the PC, monitors, modem, and anything you refuse to let reboot. Ignore the PSU’s peak rating; use a kill-a-watt or the 50–60 percent load you actually draw. Decide whether you need 5 minutes to save or 30 minutes to ride out a blink.

Example: A 200 W office load for 15 minutes is 50 Wh of battery after inverter loss. That is a mid tower UPS class, not a 350 VA strip that holds a router for two minutes.

Avoid: Matching VA to the PC power-supply sticker. VA is not watt-hours. A 1500 VA unit with a small battery still dies quickly if the load is 400 W.

How this estimate works

Multiply load watts by desired hours, adjust for conversion efficiency, and report a VA floor using a 0.7 power-factor planning assumption.

Know the limits

  • Manufacturer runtime charts override this energy estimate.
  • The result is not an electrical-code review or a ride-through guarantee.
  • Surge, battery age, and temperature change available runtime.

Frequently asked questions

How does the ups runtime work?

It converts the published inputs on this page into a planning class using a published rule. Multiply load watts by desired hours, adjust for conversion efficiency, and report a VA floor using a 0.7 power-factor planning assumption. The headline is a class such as Ups, not a vendor ranking.

Is APC Back-UPS Pro BR1500MS2 better than CyberPower CP1500PFCLCD?

This page does not rank APC Back-UPS Pro BR1500MS2, CyberPower CP1500PFCLCD, and EcoFlow RIVER 2. APC Back-UPS Pro BR1500MS2 and CyberPower CP1500PFCLCD are listed because they are real products with official pages that map to different or overlapping classes. The useful question is which class matches your inputs.

Do the product links earn Decision Lantern a commission?

Yes, when a product name or “View on Amazon” link goes to Amazon. Those are associate links. Decision Lantern may earn a commission at no extra cost to you. Official manufacturer pages are separate and are not tagged.

Sources

  1. Basics of Electricity, Energy, National Renewable Energy Laboratory. Retrieved .
  2. APC UPS Selector, Schneider Electric. Retrieved .

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