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 charging characteristics, electromotive force, and external dynamo control.
| Identifier | ExFiles\Box 54\2\ Scan097 | |
| Date | 26th June 1926 | |
| Contd. -3- EFCL/T26.6.26. This line AB and the deductions to be derived therefrom are in connection with the desirability of avoiding the excessive voltage on the chassis electrical system by the possible use of some form of external dynamo control and the line represents an arbitrary assumed suitable characteristic for a generator with such control. Taking the point P where the line intersects the sustained P.D. curve, it will be seen that the current given to the battery tends toward the limit of 2.7 amperes, and that the true E.M.F. of the battery charged by such a generator can never exceed 16.1 volt, whereas at 12 amperes charge the true E.M.F. will be 16.8 volts. The question arises as to whether, when the battery is given a tapering charge with a generator output in accordance with the line AB, the battery can be properly charged up to the same capacity as it would have if charged at the full rate, which results in a much higher final P.D. and E.M.F. We judge on the whole that such a type of charge would be better for the battery, though the fact and consequent query remain that the battery would never be fully charged in the sense of having its true E.M.F. brought up to its maximum possible value. This E.M.F. may only be due to the presence of a quantity of gas which cannot escape so readily and may not actually be necessary for complete charge of the paste, but it is a point about which we are not quite certain at present and which will bear further investigation. Contd. | ||