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).
Utility of a voltmeter as a charge indicator for car dynamos.
| Identifier | WestWitteringFiles\U\January1930-April1930\ Scan054 | |
| Date | 7th January 1930 | |
| To R.{Sir Henry Royce} from EFC. c. Sg.{Arthur F. Sidgreaves - MD} c. PN.{Mr Northey} c. E.{Mr Elliott - Chief Engineer} ORIGINAL EFC5/ATL/7.1.30. X8780, X.8780. CAR DYNAMOS AND CHARGE INDICATOR. With further reference to your R2/M28.12.29. Having given some thought to the matter of a simple and reliable indicator to shew when the battery is fully charged, we now doubt whether for practical purposes, the indications of a high grade voltmeter may not be considered as of at least as great utility as any other form of device which seems possible. To us, it appears that the difficulty of indicating the state of full charge with any device, consists largely in the fact of there being no one superficial condition of the elements or electrolyte which can be regarded as a criterion of full charge independent of previous history. Though the indications of the voltmeter suffer in a similar respect, it appears likely that it would have a certain amount of real utility as an overcharge indicator. In any case it is of such a nature as to leave the greater portion of the responsibility in the hands of the driver. It is understood that Mr.Elliott will shortly be presenting to you the joint recommendation of himself and ourselves here in regard to dynamo outputs and reduced charge switching, and that he is looking into the matter | ||