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).
Battery discharge performance test chart showing a voltage curve over time.
| Identifier | ExFiles\Box 54\1\ Scan284 | |
| Date | 8th June 1928 | |
| 5 6 7 8 9 10 11 8-6-28 177 SV 75 a.h. 103 lbs. 5 4 3 2 1 0 Average amperes = 6.48 Hours = 5.9 Ampere hours = 38.2 .371 1.80v | ||