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).
Causes of battery discharge on Bentley chassis, differentiating between high-speed and city driving conditions.
| Identifier | ExFiles\Box 58\4\ Scan195 | |
| Date | 10th December 1934 | |
| WST c. Hs{Lord Ernest Hives - Chair}/Wst. c. BY/RD. y6103 BY.6/G.10.12.34. RE: DISCHARGE OF BATTERIES ON BENTLEY CHASSIS. I had already drafted a memo on the above subject before Mr. Tonge brought me down C's memo, which is under discussion (ref. C.21/C.7.12.34.). In reviewing the situation which had been previously covered by Hs{Lord Ernest Hives - Chair}/Wst's memo and my instruction BY.16/G.7.12.34., it appeared to Mr. Davis that it was not clear from the correspondence which had passed as to exactly what state of conditions were responsible for the batteries running down, as there were obviously two distinct cases under discussion, either of which trouble might occur, the two cases in question being :- (a). High speed at night with all lighting on and large head lamps. This would be catered for by Hs{Lord Ernest Hives - Chair}/Wst's memo and our instruction based on that - BY.16/G.7.12.34. or (b). It appeared possible that the trouble might conceivably be due to the use of Bentley cars in congested city conditions, such as occur in using a car in London or Birmingham, with very little running external to the city. If this is a cause of trouble, as it would appear to be from C's memo, then I know of no remedy other than a new armature as the proposals referred to under heading (a) only result in higher output above a speed of 25 miles an hour, at which speed, of course, such increase would be useless, as it would be seldom exceeded in city conditions with heavy traffic. The only remedy that I see for such a state of affairs is a specially wound armature giving a lower resistance in order to obtain charging current at lower car speeds. It is not possible with a voltage control type of dynamo to do anything similar to that which has been suggested for the three-brush machine on the 20/25's. BY.{R.W. Bailey - Chief Engineer} | ||