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 to Rolls-Royce of America discussing a two-rate charging scheme for dynamos to prevent excessive battery overcharging.
| Identifier | ExFiles\Box 163\6\ img145 | |
| Date | 9th May 1931 | |
| X6016 Hs{Lord Ernest Hives - Chair}/CAF1/AD. 9th May, 1931. X6016 X6099 Mr. Burton, Messrs. Rolls-Royce of America Inc. Springfield, Mass. Dear Mr. Burton, Two Rate Charge Scheme. Replying to your letter ref. Btn-7 of April 29th, the above is the natural result of fitting a dynamo with a high output, the idea being to have a second or reduced output to prevent excessive overcharging. We have increased the dynamo output, and probably will increase it still further in the future, to such an extent that at present the maximum charging current during daytime running may be as high as 13 or 14 amperes. Since this high output will occur when the battery is in a fully charged condition and there is little demand on the battery for current, i.e. on long distance runs in daylight, it is obvious that in some way the output should be reduced for such occasions otherwise rapid deterioration of the battery will take place and frequent topping up be necessary. At the same time the full output of the dynamo must be available for night running when a heavy demand for current arises, especially with the use of the 60 watt headlamps which are in common use here. | ||