Frequently Asked Question
Why does my Eaton UPS run for much less time than expected during a power cut?
QUICK ANSWER
Runtime depends on actual load, battery charge, condition and temperature. The VA rating is a capacity rating, not a promise of a fixed number of backup minutes.
Applies to: Eaton desktop, NAS and server UPS systems. Use the runtime curve for the exact UPS and battery configuration.
Work through these checks
- Record the actual load in watts or the UPS's load percentage, including switches, PoE devices, monitors and storage. Check both the watt and VA limits.
- Compare that load with the exact model's published runtime curve. A runtime figure at half load cannot be expected at full load.
- Allow a full charge according to the model's instructions, then review battery age, recent discharges, temperature and any failed self-test. Heat and battery deterioration can reduce usable runtime.
- Remove non-essential loads through an agreed plan and configure timely shutdown of protected systems. Use only approved external battery options on models that support them.
Confirm the result
Perform a planned, controlled runtime/shutdown check with a safe workload. The priority is enough time for an orderly shutdown, not repeatedly discharging the UPS to zero.
Before going further: Do not add improvised batteries or open the UPS. Repeated deep-discharge tests can further stress an ageing battery.
If you need help
Include these details in your ticket: UPS/battery configuration, age, charge state, measured watts, ambient temperature and observed runtime.
Updated 261107