Blog - Tests and diagnosis

Dogma: The energy of the regular “AA” cells = 1.43Wh

Dogma: The energy of the regular “AA” cells = 1.43Wh

21.Dec 2020
| Blog - Tests and diagnosis

The AA cells are the primary one-time use cells. The nominal voltage of the AA cells is 1.5V and their capacity in Ah usually not stated in the specification. It shows that people are fooled easily. ????

Image: you buy the milk in some box every day, but you never now how much liters or milliliters you actually buy. Sometimes more, sometimes less. Yet, with the AA cells and other types of household products most people buy these as a black box with no technical specifications. We really wonder how is this possible.????????????

Most of the producers do not give any specific discharge curves and the technical data is very difficult to find. The image above shows an example from the official data provided by Duracell for the Procell Alcaline Battery.

Unlike the lithium (LFP) cells, the performance of the AA cells is influenced by the current of the load. This type of battery has a higher inner resistance and when you use more current — a part of the energy will be turned into the heat and the cell will warm.  Generally said: these AA cells should be discharged slowly in a matter of days, weeks or months.

However, to compare the performance of various cells, there has been a standing testing procedure with the 500mA current from the full voltage (typically above 1.5V) till the discharge voltage of 0.8V.

There is a test comparison video that shows the results of the AA cells from various producers. With the 500mA test the capacity ranges from 1444 mAh to as low as 1167 mAh.  Check the video here.

As a result, you can see that with the AA cells, you actually buy some energy with no guarantee of how much you actually buy.

Based on these test, the average capacity of the AA cell is around 1300mA. With the cell voltage dropping between 1.4V and 0.8V the average voltage is considered to be 1.1V.

The typical energy of the AA cell (discharged at 500mA) is 1.1V x 1300 mAh = 1.43Wh.

This value is one of the fixed dogmas of the GWL/Team.  You have to accept it, believe it and never doubt it. ????

14 visitors online.
All Rights reserved © 2021 GWL a.s.