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).
Report from Peto & Radford comparing the performance of 9-plate and 7-plate battery cells.
| Identifier | WestWitteringFiles\Q\February1927-March1927\ 82 | |
| Date | 8th March 1927 guessed | |
| -2- Contd. The 9-plate Cells. The positives in each cell projected about 3/16" above the negatives. The positives were in slightly better condition than those in the 7-plate cells but nevertheless fell to pieces when dismantled. The active material was firm. The reason for their condition the same as for the 7-plate cells. The negatives were in quite good condition and superior to those in the 7-plate. The wood separators were in a similar condition to those in the 7-plate. The ebonite separators in one cell were somewhat attacked and rubbed through, in the other cell they were in very fair condition. Conclusions. There is little to choose between the two types. Although the 9-plate components were in slightly better, there is not sufficient justification from the result of these tests to recommend a change from the present standard 7-plate section so long as they have both to be contained in the same cell. If there was a little more space available in which the 9-plate sections could be fitted, they would probably show very much better results than the 7-plate. We think, however, we can improve the 7-plate cells by an alteration to the design of the grid, which will not affect them in their early life but when they are getting old they will not buckle and grow quite so much. We are going into this and making some experiments but it will be some time yet before we can make a change and incorporate this feature. All cells failed by reason of the filling up of the ediment space and this dimension cannot be too great in our opinion, and if Rolls-Royce Ltd. did not cut us down so in dimensions we would recommend putting them up a little higher than they are even at present. The R-R bench test appears to decompose the ebonite separators to a greater extent than obtains under road and service conditions." We think that the above report from our Laboratory is very interesting and it bears out your own test. Our Laboratory think that the battery has done very well and has lasted longer than any similar battery of our own or any other make that we have tested. Yours faithfully, PETO & RADFORD. (sgd) G.R.N.Minchin. | ||