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Vehicle battery condition monitoring system

  • US 6,417,668 B1
  • Filed: 01/31/2001
  • Issued: 07/09/2002
  • Est. Priority Date: 01/31/2001
  • Status: Expired due to Term
First Claim
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1. Apparatus for monitoring a battery having negative and positive terminals, comprising:

  • a current sensor connected to a terminal of the battery for measuring current passing into and out of the battery;

    a voltmeter connected across the terminals of the battery for measuring battery voltage;

    a temperature sensor located near the battery for providing readings of ambient temperature;

    a data processing system receiving data from the current sensor, the voltmeter and the temperature sensor and including memory for the storage of programs and data;

    an engine starter system coupled for energization by the battery;

    a battery history table including records of battery condition during prior starts of the apparatus;

    an engine cranking power specification table;

    stored in the memory for providing an estimate of cranking power required to start an engine;

    a battery capacity table stored in the memory for providing estimates of battery capacity as a function of battery history, ambient temperature, open circuit voltage of the battery, voltage after a period T of cranking and current discharge during cranking; and

    a comparator utilizing the estimate of cranking power and an estimate of battery capacity as inputs to determine if battery capacity exceeds the cranking power estimate.

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