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 test result chart showing performance over time.
| Identifier | ExFiles\Box 54\1\ Scan237 | |
| Date | 2nd February 1927 | |
| X46175 2-2-27 170 SU 75 a.h. 103 lbs. Average amperes = 6.15 Hours = 4.9 Ampere hours = 37.8 .36) 1.80w | ||