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).
The results of P.D. and E.M.F. tests on six different chassis batteries, including a description of the testing methodology.
| Identifier | WestWitteringFiles\O\2April1926-June1926\ Scan244 | |
| Date | 28th June 1926 | |
| To R.{Sir Henry Royce} from EFC. c. BJ. PN.{Mr Northey} Wor.{Arthur Wormald - General Works Manager} c. E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} Rg.{Mr Rowledge} c. By.{R.W. Bailey - Chief Engineer} EP.{G. Eric Platford - Chief Quality Engineer} ORIGINAL RE BATTERIES. As referred to in the covering note EFC3/T16.6.26 of our EFC1/T12.6.26, we have now completed on six chassis batteries some charging P.D. and E.M.F. tests at various rates of charging current. The batteries tested comprise each of the four standard chassis batteries, together with two special batteries (Exide and P & R )with threaded rubber separators. Prints of the results of these tests exhibited in the form of curves are attached. The figures from which these curves are plotted come out quite nicely and can quite well be repeated coming down as compared with going up with the charging rate, so that they do represent the actual state of affairs when in use practically accurately. We should perhaps state that the batteries were previously taken up to the fully charged condition. In order to arrive at the true E.M.F. of each battery, we have a switch which we can knock over to throw off the charging current and then note the instantaneous balance of the P.D. of the battery under test (E.M.F.) through a null instrument against a similar voltage put up from an auxiliary battery with potentiometer adjustment. The value of the auxiliary E.M.F. which allows no initial kick on the null instrument at the instant of switching over is the true charging E.M.F. of the battery on test as nearly as can be arrived at experimentally. It will be noticed that the | ||