AN417

Charge termination methods

Doc ID 2074 Rev 2

7/21

2.2

The inflexion point method

A second charge termination method much more adapted to NiMH batteries consists of

detecting the inflexion point of the voltage curve, thus avoiding any excessive overheating of

the battery. This method therefore significantly increases the battery life-time.

Figure 3.

Fast charge terminates at point B in the inflexion point method

charging time

cell voltage

battery voltage

battery temperature

temperature

1.2

1.3

1.4

1.5

1.6

20

30

40

50

60

deg C

V

B

A