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).
Letter discussing battery performance concerning temperature, age, and wooden container specifications.
| Identifier | ExFiles\Box 168b\3\ img148 | |
| Date | 10th February 1928 | |
| V1535 P EFC4/T. 10th February, 1928. Mr. G.R.N. Minchin, Messrs. Peto & Radford, 50, Grosvenor Gardens, London, S.W.1. X4058 Dear Mr. Minchin, Your letter of the 6th inst. Thank you for your remarks concerning the question as to whether the battery elements will lose ground as regards their chemical condition. Also your remark has been noted concerning the P.D. across the battery terminals as affected by temperature. This P.D. is less as the battery is warmer. The P.D. of a battery is also less with age. Both these points are a little bit of a difficulty, necessitating setting the auto switch at what will appear to be in some circumstances an unnecessarily early figure. We are therefore considering the possibility of some kind of temp: compensation, such as mounting the fixed contact point on a bimetal support in such a way as to correct the temperature variation. Another way of course is to have a non-temperature coefficient resistance in series with the shunt coil, but this only goes half way, adds complication, and is to be avoided if possible. We have now received the three sets of 12V batteries in six 6-volt units, and we thank you for your efforts in this direction. In regard to your last paragraph, I have duly put this before those concerned. They say that according to our drawings the thickness of the woodwork for the wooden containers in our temporary scheme should be 1/4" when using the 40/50 size of cells, but we believe that owing to some misunderstanding the P & R.{Sir Henry Royce} Co. have not given us this thickness in the experimental batteries supplied. On examination of these batteries we find the thickness of the wood is .2", but owing to the metal corner plates the overall width of the battery is such that Contd. | ||