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METHOD AND APPARATUS FOR DETERMINING BATTERY PERFORMANCE AT ONE TEMPERATURE WHEN BATTERY IS AT ANOTHER TEMPERATURE

  • US 3,876,931 A
  • Filed: 12/26/1973
  • Issued: 04/08/1975
  • Est. Priority Date: 01/14/1972
  • Status: Expired due to Term
First Claim
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1. The method for testing a lead-acid storage battery, with accuracies at least adequate for automotive service station battery testing purposes, to provide an observable indication of whether the battery is capable of delivering a stated cranking current at a predetermined temperature when the battery is in fact at a different temperature, comprising discharging the battery through a known load resistor at a current different than the stated cranking current for a short period of time;

  • deriving from the battery while it is still being so discharged a first electrical quantity representative of the actual terminal voltage of the battery at the end of said period of time;

    sensing the actual temperature of the battery;

    developing a second electrical quantity representative of the difference between said actual temperature and said predetermined temperature;

    developing a third electrical quantity representative of the difference between said stated cranking current and said current obtained by discharging the battery through said known load resistor; and

    converting said first electrical quantity into an observable indication which differs from that which would accurately indicate the terminal voltage of the battery by amounts representative of the algebraic combination of said second and third electrical quantities.

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