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).
Proposal to use thin plate batteries, their performance benefits, and associated considerations.
| Identifier | ExFiles\Box 58\4\ Scan257 | |
| Date | 22th April 1936 | |
| To Sg.{Arthur F. Sidgreaves - MD} c. to Wor.{Arthur Wormald - General Works Manager} c. to By.{R.W. Bailey - Chief Engineer} c. to Roy.{Sir Henry Royce} HS{Lord Ernest Hives - Chair}/Wst.1/JH. 22.4.36. Thin Plate Batteries. With reference to E.S/EP.{G. Eric Platford - Chief Quality Engineer}18.4.36., and By.7/W.214.36. we originally proposed the use of thin plate batteries because it immediately gave us much improved starting under very cold conditions for the following reasons :- (a) The external resistance being about 10% less reduced the volt-drop across the battery and thereby increased the speed of the motor. (b) As the plates were much thinner it was possible to gain two extra plates per cell, and due to the reduced thickness a more rapid release of electrical energy occured at the high rates of discharge over a given time. This was very evident when we charged to a thin plate battery during an attempted cold start on 21-G-IV in Messrs. Lucas's Cold Room. We took the car over with one of our own standard batteries fitted, which only turned the engine over very slowly, and very quickly reached the condition of discharge, where it would not turn the engine over at all at any appreciable speed. We then took a standard Lucas battery as fitted to cars like Moris Oxford and Standard, and the engine spun round considerably faster and maintained this speed for a longer period of time. We must accept however that the life of our batteries will be reduced when we change over to these thin plate batteries. So much depends on the treatment of the battery in customers hands, and it is up to us to see that our dynamo and regulator system always charge the battery rapidly when discharged, and does not overcharge at high rates. The dynamo is now capable of meeting these heavy current demands but the C.A.V. regulator we use is not suitable for a rapid heavy charge at low | ||