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).
And suggesting the actual battery capacities for 40/50 HP and 20 HP chassis.
| Identifier | ExFiles\Box 54\2\ Scan062 | |
| Date | 10th August 1925 | |
| X4617 To BY {R.W. Bailey - Chief Engineer} /HEB. {H. Biraben} from EFC. {E. Fowler Clarke - Electrical Engineer} EFC {E. Fowler Clarke - Electrical Engineer} 1/T10.8.25. X.664 - BATTERIES FOR 40/50 AND 20 HP. CHASSIS. X4617 X4642 With reference to the attached we cannot give very definitely the actual capacities of the batteries, but suggest that they be put down as 75 ampere hours for the 40/50 HP. and 50 ampere-hours for the 20 HP. The actual ratings on the P & R labels are 80 and 50. On the Exide labels there are no ratings. In a general way the Exide batteries give their full capacities after two charges, whereas the P & R batteries only give 2/3 of their ratings at first. Though time is not far enough advanced for us to have observed the actual capacities of these new batteries after a fair amount of use, we know from previous observations that the P & R capacities will increase to values approximately equivalent to what we are giving. The figures in the specification are 65 and to 75, for the 40/50 and 45 to 55 for the 20 HP. We suggest for the present purpose that the actual capacities be stated as 75 and 50 ampere hours respectively. EFC. {E. Fowler Clarke - Electrical Engineer} | ||