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).
Chart detailing the characteristic curve of an S1 battery during charging.
| Identifier | ExFiles\Box 54\1\ Scan234 | |
| Date | 1st January 1927 | |
| 1-1-27 154 S1 battery charged to characteristic V=17 - .25A 2 Average amperes = 6.16 Hours = 9.5 Ampere hours = 58.5 .580 1.80w REG'D TRADE MARK "MECCERT" | ||