METHOD OF TESTING THE CAPACITY OF A LEAD-ACID BATTERY

• US 3,808,522 A
• Filed: 11/03/1972
• Issued: 04/30/1974
• Est. Priority Date: 11/03/1972
• Status: Expired due to Term

• Current Assignee: Harold M. Sharaf
• Original Assignee: Harold M. Sharaf
• Inventors: Sharaf, Harold M.
• Primary Examiner(s): Smith, Alfred E.
• Application Number:
  US05/303,305
• Time in Patent Office: 543 Days
• Field of Search: 324/29.5 320/48
• US Class Current: 324/430
• CPC Class Codes: G01R 27/02 Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant by measuring phase angle only G01R25/00
• CPC Class Codes: G01R 31/379 for lead-acid batteries
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A method of testing the capacity of a lead-acid battery where the internal resistance of the battery is initially measured when the battery is relatively young and the internal resistance is subsequently measured periodically. By comparing the values obtained on these subsequent measurements with the initial value, it is determined when a substantial increase occurs in the internal resistance of the battery. This substantial increase indicates that the battery is near the end of its life.

Claims

1. A method of testing the capacity of a load-acid battery comprising the steps of:

initially measuring the internal resistance of said battery when the specific gravity of the battery'"'"''"'"'s electrolyte is greater than 1.150;

subsequently measuring the internal resistance of said battery when the specific gravity of the battery'"'"''"'"'s electrolyte is greater than 1.150; and

, comparing the values of the initial and subsequent measurements to ascertain if the value of said subsequent value exceeds the value of said initial value by a predetermined amount.

2. The method as recited in claim 1 wherein said initial measurement is made when said battery is relatively young.

3. The method as recited in claim 2 and including recording said initial measurement directly on said battery so that it may be later compared with the value of said subsequent measurement.

4. The method as recited in claim 2 wherein said predetermined amount by which said subsequent value is to exceed said initial value is about one-half said initial value, thereby indicating that about only 10 percent of said battery'"'"''"'"'s useful life remains.

5. The method as recited in claim 2 including periodically repeating said subsequent measuring of the internal resistance of said battery and said comparing of said subsequent values obtained with said iniTial value, until one of said subsequent values exceeds said initial value by a predetermined amount.