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).
Comparing different battery options and specifications for the 40/50 car model.
| Identifier | ExFiles\Box 38\5\ Scan254 | |
| Date | 23th October 1922 | |
| X.3398 To Da.{Bernard Day - Chassis Design} from EFC. EFC4/T23.10.22. X.3398 - PETO & RADFORD BATTERY. Thank you for your letter Dal/M20.10.22. The answers to your questions are as follows :- (1) The P & R BD.{Mr Berend}11 battery has not been specially made for the 40/50 car with a view to fulfilling our specification. The particular feature by which the battery containing case is done away with is their own and I believe they have a patent for the method of securing the battery to the running board. Actually the battery more than fulfills our specification of performance. As against this, however, our present standard Exide battery, since the modifications necessary to avoid short circuiting by buckling, actually does not quite fulfill our specification as regards internal resistance or high rate discharge current. Whilst it is true that they can make a battery equivalent to our standard for say 20 lbs. less weight, it can only be say 10 lbs. less in order still to comply with our specification. Seeing that our specification is intended to be the lower limit, it is evident there should exist no conception that the BD.{Mr Berend}11 battery is unnecessarily large. (2) The only alternative source of supply of batteries which we think would be at all satisfactory in addition to the Exide and P & R, is the C.A.V. (Willard) which when backed up by decent service would give reasonable satisfaction to the customer although the life would not be great. The P & R battery is constructed on lines of durability and long life without depending so much upon service, and it is for this reason, especially as service in this country can never be as good as in the States, that we think, taken allround, the P & R battery will be the more suitable of the two. The C.A.V. battery is undoubtedly excellent when kept in good condition and is also of very low internal resistance and high cranking ability for a given weight, when kept in good order. In the case of the Goshawk you may know we are ordering batteries of all three makes, but in this case Contd | ||