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).
Investigation into the internal resistances of various lighting and starting batteries.
| Identifier | WestWitteringFiles\C\May1919\ Scan36 | |
| Date | 12th May 1919 | |
| To R.{Sir Henry Royce} from EPC. c.c. to CJ. c.c. to EY. c.c. to Da.{Bernard Day - Chassis Design} c.c. to HH. EFC1/12.5.19. ORIGINAL. X.664 - BATTERIES. (INTERNAL RESISTANCES). We have carefully investigated the matter of internal resistances of the various lighting and starting batteries we have received, and we find considerable variation in the different batteries. The various batteries were compared with one another in a fully charged condition and with all acid densities adjusted to between 1245 and 1265. In one method of comparison we connected each battery in turn through a switch to the starter motor, which was braked with a certain load. We noted the open circuit voltage, which we always arranged as far as possible to be between 12.0 and 12.5. We then switched on current and noted the maximum reading to which the voltmeter fall, and also the reading at which the voltmeter stood when the motor speed had attained such a value that the current had fallen to a certain value, in this instance, 90 amperes. The following table represents results of these tests:- Contd. R.R. 235a 500(I) S.D. 408 26-4-17(.) Bm. 2/156/13. | ||