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).
Starter motor performance, comparing its battery system to American 12-volt systems and evaluating alternative batteries.
| Identifier | WestWitteringFiles\G\September1921\ Scan54 | |
| Date | 13th September 1921 | |
| R.R. 985A (100 T) (S.H 159. 11-8-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2800 EFC1/T13.9.21. -5- Contd. of 1 volt drop from 12 volts per 50 amperes is more suitable for some ~~test~~ purposes, at any rate, in the case of our own starter motor with present cable and battery, especially as at the moment conditions on the car may be a little worse than even this characteristic would assume. We very much doubt if the actual performances on American cars using 12 volt systems and heavier batteries and cables than ours are working normally anywhere near this S.A.E. standard characteristic, unless as mentioned before, the batteries happen to be in an absolutely fully charged condition. We realise that our own present standard arrangement must necessarily be quite incapable of coping with the extreme conditions in U.S.A. and therefore it has been necessary to substitute a motor with much lower resistance windings and capable of developing more power for the same weight. At the same time, to secure the full advantage of such a motor, it has, of course, been necessary to reduce the resistance of the starter cables and the battery, as if these two latter items were not attended to, the speed of revolving an engine might actually be reduced. We now have a sample Willard S.J.R. G.28 battery which came back with 4 EX and no doubt Mr. Olley will be interested later to hear the results we obtain with this battery on the bench discharging through .100 ohm resistance, and especially in comparison with the Exide 6-LXR-9-1, of which we also have a sample. Contd | ||