An UPS (Uninterruptible Power Supply) consumes energy both when operating on the battery and when on mains power. The exact energy consumption of a UPS can vary depending on several factors, such as the brand and model of the UPS, the load connected to it, and the efficiency of the UPS.

When determining the energy consumption of a UPS, there are two important aspects to consider:

1. Standby consumption: Even when there is no power interruption and the UPS is working on mains power, the UPS consumes a small amount of energy to remain operational. This is often referred to as the “standby consumption.” The standby consumption can vary, but it is typically relatively low.

2. Efficiency: When the UPS switches to battery mode during a power outage, energy consumption can increase due to the conversion of direct current from the battery to the alternating current needed by the connected equipment. The efficiency of a UPS indicates how much of the energy drawn from the battery is actually available to the connected equipment. Generally, UPS models with higher efficiency have less energy loss during conversion.

It is important to consider the energy consumption of a UPS when choosing a model, especially if you want to account for power usage and associated costs. Consult the technical specifications of the specific UPS you are considering to find detailed information about the energy consumption in different operating modes.