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).
Comparison of performance curves (Volts vs. Amperes) for two different standard 40-50 HP batteries.
| Identifier | WestWitteringFiles\O\2April1926-June1926\ Scan249 | |
| Date | 26th June 1926 guessed | |
| Left Graph: VOLTS AMPERES SUSTAINED P.D. TRUE EMF. A P B STANDARD 40-50 H.P. P&R R R II Right Graph: VOLTS AMPERES SUSTAINED P.D. TRUE EMF. STANDARD 40-50 H.P. EXIDE 6RR5 | ||