Blog - Battery Monitoring

The demonstration of function of the CBM boards

The demonstration of function of the CBM boards

22.May 2011
| Blog - Battery Monitoring

The demonstration of function of the CBM boards

The CBM boards (Cell Ballancing Module) will start balancing of the cell as soon as the full charge level is reached. The full charge level is is at 3.60V for LiFePO4 cells.

The diagram shows the charging of a 4-cell battery pack with following configuration:

Cell1 - no CBM board installed
Cell2 - one CBM board installed (balancing up to 1.7A)
Cell3 - two CBM boards installed (balancing up to 3.4A)
Cell4 - three CBM boards installed (balancing up to 5.1A)

The first part of the diagram shows the charging with 1A current. The Cell1 (with no CBM) goes over the 3.8V level and the voltage would increase very rapidly. Cells2, 3, 4 are ballanced with the CBM modules and the voltage is kept bellow 3.6V.

The second part of the diagram shows the charging with 3A current. The Cell1 (with no CBM) goes over the 4.4V level and is OVERCHARGED. The Cells 2 (with one CBM) is balanced and the voltage increases slowly. However ONE CBM (balancing up to 1.7A) is not enough for the 3A charging current. As a result the voltage would also increase above 3.8V, if not stopped. Only Cell3 and Cell4 (with 2 and 3 CBM boards) are ballanced sufficiantly and the voltage is kept bellow 3.6V.

This demonstration shows that the CBM boards can balance the LiFePO4 celss easily, however for higher currents, more CBM boards needs to be connected together to increase the total balancing current.

Tip: you can check the CBM pricing here.   Support: You can download the test data source here

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