From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Life breakdown test performed on a sample storage battery from the Cadillac Motor Car Company.
| Identifier | ExFiles\Box 41\2\ Scan097 | |
| Date | 23th April 1919 guessed | |
| REPORT ON SAMPLE STORAGE BATTERY FOR LIFE BREAKDOWN TEST FROM THE CADILLAC MOTOR CAR COMPANY, DETROIT, MICH. This storage battery was subjected to a life test which began October 1, 1917 and ended January 30, 1918, a period 480 days during which time the battery was subjected to a constant rate of charge 7 amperes, except for 10 ampere discharges which were made approximately one month apart as hereinafter noted. See chart for data. The total amount of time on charge was 7,759 K.{Mr Kilner} W. hrs. The following table gives the data recorded when pre-liminary test discharges were made: Discharge Rate Date Voltage max. min. Sp.{Mr Spinney} Gravity max. min. Temperature max. min. Amp.Hr. Rate 10 8-13-17 6.8 4.7 1.300 1.120 85 78 135.6 10 8-21-17 6.5 4.9 1.305 1.105 85 80 152.5 5 8-15-17 6.5 5.0 1.300 1.085 88 78 157.5 5 8-24-17 6.5 4.9 1.300 1.090 83 68 158.3 160-50 8-31-17 6.6 3.0 1.300 1.250 100 78 20 min. After these tests were completed the battery began the life test and continued for 96 days when it was discovered that the center cell was dead. Under ordinary circumstances this would have completed the test of the sample, but upon examining the dead cell the plates were found to be in excellent condition in every respect except for the fact that a surplus of active material on the grids had flaked off too much an extent that it shorted the cell by making the contact over the edge of the glass partition, and the test continued. When considering the total performance of the battery this extra treatment should be borne in mind. Curves for the thirteen discharges are attached herewith together with a chart summarizing the most important features of the life test. It will be noted that the final discharge had run only a few minutes when further readings were found to be impossible. It was found that the Negative Cell caused the failure and upon opening the cell it was discovered that the Positive grids had cracked and grown upward, or expanded, to such a height that the cell was shorted. The top and bottom edges of the Positive grids were badly cracked but the center sections remained intact. Inspite of the fact that the grids were cracked the active material remained in place and as a consequence there was very little sediment in the bottom of the jars. The grids were found to be in good condition and contained plenty of lead. The openings in the grid are square in shape and are staggered so that the openings on one side half way clears a similar opening on the reverse side. | ||