Comparing P+R Standard and Exide threaded rubber battery separators.
| Identifier | ExFiles\Box 54\5\ Scan120 | |
| Date | 19th July 1929 guessed | |
| J.D.16. 2 P+R. {Sir Henry Royce} Standard. Exide Threaded Rubber. P+R Standard. By this it seems that threaded rubber separators suit the P+R better than the Exide especially with the rib facing the positive plate. This has been the case throughout the life of the battery. G.H. | ||
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).