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 chart for a C.A.V. Willard 12XR2 battery from chassis 57.S.H.
| Identifier | ExFiles\Box 47\4\ Scan041 | |
| Date | 9th January 1925 | |
| X4914V 9-1-25 C.A.V. Willard 12XR2 battery from chassis 57.S.H. REGD TRADE MARK EGCERT Average amperes = 5.25 Hours = 3.75 Ampere hours = 19.7 .298 2.34w | ||