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Smartphones, slate tablets, cordless phones, and other mobile phones

Energy efficiency classes and battery durability

Energy efficiency classes

The energy efficiency class of a smartphone or tablet is determined based on the energy efficiency index (EEI). The EEI represents the operating time of a device without recharging, divided by the battery’s energy capacity — the higher the value, the better.

Table: Energy efficiency index (EEI) and the corresponding energy efficiency classes

Energy efficiency class

Energy efficiency index (EEI)

Smartphones

Tablets

A (most efficient)

> 2,70

> 7,90

B

> 2,30 

> 6,32

C

> 1,95 

> 5,06

D

> 1,66 

> 4,04

E

> 1,41

> 3,24

F

> 1,20 

> 2,59

G (least efficient)

≤ 1,20

≤ 2,59

Calculation of the EEI

The EEI shall be calculated with the operating system version installed on the product model on the date of placement on the market.

Detailed information on measurement and calculation methods can be found in Annex IV., and, until a harmonised standard is available:

Battery durability

The battery endurance (ENDdevice) is the number of hours and minutes a smartphone or slate tablet can operate starting with a fully charged battery until the device automatically shuts down due to an empty/drained battery.
 

The energy efficiency index (EEI) of a smartphone or slate tablet is calculated using the following equation and rounded to two decimal places:

Where:

  • EEI is the Energy Efficiency Index in 1/W,
  • Unom is the nominal voltage in V,
  • Crated is the rated battery capacity in mAh.