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).
Comparison report on the failure of C.A.V. and Exide batteries after a life test.
| Identifier | WestWitteringFiles\L\July1924-September1924\ Scan51 | |
| Date | 4th September 1924 | |
| Contd. -2- EFC8/T4.9.24. but once or twice a week it would be subjected to a partial discharge. This set was started off with three 20 HP. batteries one of each make which had already done nearly similar amounts of running on chassis. Recently these three batteries have all failed in this life test, and curiously enough all about the same time. Two cells of each battery have been opened up and examined and detailed reports on the results of the examination are attached, which may be read if desired, but the more salient points of comparison are as follows :- C.A.V. Battery. Poor battery case, badly rotted with acid. Large quantity of sediment in cells, causing short circuits. Poor cell cases, liable to crack. Threaded rubber separators in excellent condition, no suggestion of clogging and increase of internal resistance of the battery therefrom, as has often been suggested to us by competitors. We are of the opinion that this form of separator is particularly good, no possib-ility of short circuits from plate to plate taking place. The battery failed owing to deterioration of the positive plates, and short circuiting ocurring through sediment, the condition of the positive plates being decidedly the worst of the three. Exide Battery. The battery case fairly sound. Wood separators in good condition. Additional ebonite separators chafed thin and in holes. Cell cases very thin and weak and liable to crack. This also applies to the plate supporting ribs at the bottom of the cell. Sediment room insufficient- less sediment proportionally than in the case of the C.A.V. + threaded rubber Contd. | ||