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).
Testing the terminal potential difference and electromotive force of a P & R 6FR11 battery cell.
| Identifier | ExFiles\Box 54\1\ Scan084 | |
| Date | 30th January 1926 | |
| X4617P EFC. 30.1.26. JC.4. RE TERMINAL P.D's OF CELLS. X664 A std. P & R 6FR11. battery was fully charged and when gassing the current was increased to 12 amperes for a short while until each cell P.D. was steady. The current was then switched off and the terminal P.D. of one cell was taken at different intervals whilst on open circuit, thus giving the true momentary E.M.F. A rough graph has been plotted (herewith) and it will be seen that the E.M.F. falls off very quickly at first and then gradually steadies itself down. The cell E.M.F. did not get stationary until it had stood for approx. 2.5 hours when it had dropped to 2.14. To obtain the E.M.F. for a 12 volt battery it will be necessary to multiply the cell E.M.F. by 6, as readings were only taken on one cell, all the others being equal. GJ. | ||