Battery discharge test chart showing average amperes, hours, and total ampere-hours.
| Identifier | ExFiles\Box 54\1\ Scan332 | |
| Date | 7th January 1926 | |
| END OF CHART APPROACH X4617S 7-1-26 171 SZ 75ah. 101 lbs. Average amperes = 6.15 Hours = 5.9 Ampere hours = 36.3 .360 1.80w REGD TRADE MARK 'MEGGER' | ||
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).