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).
Letter from Peto & Radford discussing battery life, cost, weight savings, and cover options for Bentley cars.
| Identifier | ExFiles\Box 58\4\ Scan230 | |
| Date | 18th December 1935 | |
| PETO & RADFORD. CONTINUATION 2. Messrs. Rolls-Royce, Ltd., 18th December, 1935. with less owing to the geared starter. It is very difficult to estimate life but as you are sure to ask us about this, we must make a shot at it and say that it ought to last from 2 to 2 1/2 years. The battery would have the same double separation as at present. With regard to the cost, although it is a smaller battery it is more expensive proportionately to make owing to the carving down of weight and the fact that the plates and other parts are not those that are used in the same large quantities as with your present battery. The price to you therefore would be the same. If you scrap the cover, there would be a saving of weight off your present battery of 2 1/2 lbs. and off the 6.HZD.9-S of 2 lbs.⊗ and we think you might very well take this saving or at any rate try a battery without cover to see if it does get muddy or dirty on the top. The absence of the cover certainly makes the servicing, topping up, slightly easier. As to the desirability of such a battery, we think that with the special circumstances surrounding the Bentley car and its importance of performance, that the installation of a battery of this sort is a permissible thing to do especially in view of your latest dynamo and starter. If owners complain that their battery will not last as long as those on Rolls-Royce cars, we think they should be openly told that the battery weight has been cut a bit because of helping performance and the batteries do need renewing slightly more frequently. The cost of them, however, is very much less than it used to be and the battery expense would be less than it was in the old days when the more expensive batteries lasted longer. We looked into the question of making a light ply-wood or papier-maché cover and cannot recommend it. They would be more expensive with very little weight saving and the materials would probably be attacked by acid in due course and the whole thing would look like "nothing on earth" in a short space of time. You will remember we made a special light weight moulded cover for your present battery which involved tool cost and for the 6.HZD.9-S, we have only got the standard cover and if you want a cover, we should presumably have to make a special light weight one for this which would involve tool cost. If, however, you decide [Handwritten note at bottom] ⊗ A specially lightened cover, as referred to in the bottom paragraph | ||