Abstract: A vehicle starting battery cold-cranking amps meter and associated method includes providing a current source, a voltage meter, a current meter and a control. The current source produces a current pulse during a brief time interval at a known magnitude that is less than rated cold-cranking amps of the vehicle starting battery being tested. The volt meter measures battery terminal voltage of the vehicle storage battery being tested while the current source is sourcing current to or sinking current from the vehicle starting battery being tested. The control determines internal impedance of the vehicle starting battery being tested from the terminal voltage of the vehicle starting battery while the current source is sourcing current to or sinking current from the vehicle starting battery being tested and determines cold-cranking amps from the internal impedance and an output of the temperature meter.

Abstract: An apparatus and method for measuring electrical characteristics of an energy delivery system utilizes a voltage sensitive circuit such as a voltmeter, a controllable current source or sink and a microcomputer. The microcomputer controls the current source or sink in order to source at least one predetermined current pattern or to sink at least one predetermined current pattern from a portion of an energy delivery system. The voltage sensitive circuit responds to a voltage developed in response to the current pattern and the microcomputer calculates at least one electrical characteristic of the energy system as a result of the response.