System and method for monitoring a vehicle battery

A system for monitoring the condition of a battery installed in a vehicle having an engine, said system comprising:

• a voltage sensor for determining the voltage of the battery at the time of starting of the vehicle engine;
• a current sensor for determining the current drain of the battery at said time of starting of the engine;
• and
• computer means for computing the rate of change of the battery dynamic internal resistance (IR) and the rate of change of the battery dynamic polarization resistance (PR) based on determinations of voltage and current by said voltage sensor and said current sensor at different times of vehicle engine start, said computer means further including means responsive to said dynamic IR increasing and said dynamic PR decreasing for initiating an indication of at least one of possible battery terminal corrosion or loose connection of a cable connecting a terminal of the battery to the vehicle electrical system.

A system for monitoring the condition of a battery in a vehicle having an engine, said system comprising:

• a voltage sensor for determining the voltage of the battery at the time of starting of the vehicle engine;
• a current sensor for determining the current drain of the battery at said time of starting of the engine;
• and
• computer means for computing the rate of change of the battery dynamic internal resistance (IR) and the rate of change of the battery dynamic polarization resistance (PR) based on determinations of voltage and current by said voltage sensor and said current sensor at different times of engine start, said computer means further including means responsive to said dynamic IR decreasing and said dynamic PR increasing for initiating an indication of the battery being unable to start the engine below a certain ambient temperature.

A system for monitoring and reporting on the condition of a battery installed in a vehicle having an engine and an ignition, said system comprising:

• a voltage sensor four determining the voltage across the battery terminals under conditions of current drain of the vehicle electrical system up to a predetermined current drain value (QV);
• an ignition sensor to determine if the vehicle ignition is on;
• a starter sensor to determine if the engine starter is on;
• an engine sensor to determine if the engine is running a self sustaining speed;
• and
• means for calculating the battery state of charge (SoC) on the basis of the measured QV, said calculating means including engine start up condition determining means for producing an indication that there is an engine start failure and the battery is losing charge in response to a determination of the ignition being on, a determination of the starter being off for more that a predetermined time, and a determination of the engine not being at a self-sustaining speed.

A method for monitoring the condition of a battery installed in a vehicle having an engine, said method comprising:

• determining the voltage of the battery at the time of starting of the vehicle engine;
• determining the current drain of the battery at said time of starting of the vehicle engine;
• computing the battery dynamic internal resistance (IR) and battery dynamic polarization resistance (PR) on the basis of the voltage and current determined by voltage and current sensors;
• computing the rate of change of dynamic IR and dynamic PR based on determinations of voltage and current at different times of vehicle engine start;
• and
• producing an indication of a specific battery condition in response to said dynamic IR increasing or decreasing while said dynamic PR is increasing or decreasing.