Battery cell's mileage and bench life test duration.
| Identifier | ExFiles\Box 54\1\ Scan340 | |
| Date | 22th July 1929 guessed | |
| 2 K JD {J. Draper - Frames} 14. bars facing inwards. No 4 cell was originally in S4 Battery & has ran 31,051 miles & has been on our bench life test 29 months. g.f. | ||
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).