Chart recording of an electrical test showing amperage over a 12-hour period.
| Identifier | ExFiles\Box 58\3\ Scan202 | |
| Date | 19th March 1930 | |
| 19-3-30 219/20 P+RRRNII-7+8 75a.h. 114 lbs. Average amperes = 6.38 Hours = 12.0 Ampere hours = 76.6 .672 1.80w | ||
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).