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).
Performance graph chart from an S1 battery test.
| Identifier | ExFiles\Box 54\1\ Scan235 | |
| Date | 5th January 1927 | |
| 5-1-27 154 S1 Battery charged to characteristic V = 17.25A Average amperes = 6.20 Hours = 9.6 Ampere hours = 59.5 TRADE MARK "MEGGER" .589 1.80W 3/1 | ||