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 discharge and life tests, comparing experimental and standard models.
| Identifier | ExFiles\Box 164\3\ img179 | |
| Date | 10th June 1938 | |
| -2- Rm {William Robotham - Chief Engineer} /RC. {R. Childs} 18/JH. 10th June, 1938. This test consists of discharging the battery at 280 amperes and measuring the available voltage at the battery terminals. (4) High rate discharge. In this test the battery is discharged on a constant resistance of .100 ohm down to 8.0 volts. Current readings are taken at short intervals and a curve of current against time plotted. This not only serves as a check on No.3, but gives an indication of the capacity. The number of minutes that the battery provides a current of 100 amperes, or over, is taken as a figure of merit. (5) Life test. (6) Cost. We consider test (3) to be most important and in respect to (3b) the experimental 6HZD11-G battery give the best performance of any battery of this class, that we have tried (apart from a Lucas battery which we have recently tested full details of which will be supplied later) On this test the terminal voltage was 9.71 volts, some delay has occurred in carrying out (3A) owing to the necessity of constructing a portable rig for use in the 'cold chamber'. On test (4) the experimental battery again proved to be superior, having a maximum current of 110.5 amperes as compared with 109.5 amperes on the standard 25/30 type battery, and maintaining a current of 100, or more amperes for 14.25 minutes against 13.6 for the standard. We appreciate that these are not complete results, but we hope to be able to forward within a few days, a tabulated set of results based on the above series of tests. The life test results will not of course be included owing to the time that the test takes. In connection with this, we should be glad to know what you consider would be suitable charge and discharge rates for an intensive life test on your 6HZD11-S and 6HZD11-G type of battery. Yours faithfully, FOR ROLLS-ROYCE LTD | ||