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).
Battery charge reduction, weight saving, and a proposed automatic cut-off system.
| Identifier | WestWitteringFiles\R\October1927-December1927\ Scan009 | |
| Date | 10th May 1927 | |
| EFC.) FROM R G.{Mr Griffiths - Chief Accountant / Mr Gnapp} to Dj. WCH. BY.{R.W. Bailey - Chief Engineer} E.L. ORIGINAL BATTERY - AUTO: CHARGE REDUCING. Mr. Minchin thinks that for many of our 40/50 open cars we could use a smaller battery - i.e. the 20HP., saving 45 lbs. weight,(on the sports car for instance.) The magnetic scheme of charge reduction is awaiting EFC. to try more than 50% reduction, which I understand is already working on some of our experimental cars. If we try to get a very small charging current we may be running into instability, and I am inclined to think we might get the results better by arranging to automatically cut off the charge entirely when the battery is fully charged, and the voltage arrives at say 16/17 V.{VIENNA} in the following way - [Diagram Annotation Right] This contact breaks at 16/17 V.{VIENNA}, adds very high non-inductance resistance to the dynamo field circuit; dynamo ceases to charge, and ordinary charging auto: switch cuts it out. This contact would not remake until voltage falls to say 10/12 V.{VIENNA} or the charging switch is broken [Diagram Annotation Bottom] Voltage coil across battery via switchbox only on when charging switch is in "on" position. Let me know if this can be done. BATTERY IGNITION. Push on with the scrubbing contacts. R.{Sir Henry Royce} | ||