Basics

A beeping UPS is reporting a condition, not automatically announcing a dead battery.

The UPS stays on during an outage, but the computer turns off immediately.

A backup inverter can deliver the expected voltage and still make a device buzz, run poorly, or refuse to operate.

An online double-conversion UPS can keep its inverter supplying the load as the input source changes to battery.

A portable power station rated 1000Wh does not automatically run a 100W appliance for exactly ten hours.

A refrigerator may consume relatively modest power once its compressor is running and still overwhelm a portable power station at startup.

A UPS reports that its self-test passed, yet the protected equipment runs for far less time than expected during an outage.

A power station that can charge while supplying an appliance does not automatically provide suitable uninterrupted backup for that appliance.

A UPS marked 1000VA may have a watt rating well below 1000W.

Doubling the load on a UPS does not guarantee exactly half the runtime.