Method and apparatus for charging storage batteries to full capacity

A circuit array for charging a storage battery, in particular for NiCd (nickel cadmium) and NiH (nickel hydride) cells, comprising:

• a charging current source for connection to a battery;
• means for cyclically separating said charging current source from said battery for a certain period of time in order to generate measurement intervals;
• means for cyclically comparing a charging voltage at the source with a stored reference value during said measurement intervals and, if the value of said charging voltage is greater than said reference value, for increasing said reference value by a certain amount to match said reference value to an actual measured value of said charging voltage and for then storing the increased reference value, said means for comparing including a peak value memory and a pulse generator for generating a clock signal for said peak value memory;
• means for counting the number of measurement intervals in which the value of the measured charging voltage is consecutively equal to or less than the stored reference value, with said means for counting including an up-down counter that is set at the start of a charging operation to the highest or lowest count and logic circuit means, controlled by comparison results from said peak value memory, for switching said up-down counter into its up mode or down mode, respectively, when the increased reference value is stored, and for switching said up-down counter into its down mode or up mode, respectively, when the actual value of said charging voltage is less than said stored reference value;
• and,
• means, responsive to a preset count in said up-down counter, for switching off said charging current source or for reducing charging current step by step depending on said count in said counter, said means for switching including a D/A converter connected behind said up-down counter and supplying a control voltage corresponding to said count of said up-down counter to said charging current source to control the charging current.