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).
Adjustment of an auto switch for battery charging voltage and performance under different conditions.
| Identifier | WestWitteringFiles\R\2December1927-February1928\ Scan160 | |
| Date | 9th February 1928 | |
| EFC2/T9.2.28. -5- Contd. This means that the switch must be adjusted to use a comparatively early part of the final pick-up of battery charging voltage instead of the later portion, and the query arises as to whether in these circumstances the battery may lose ground in the long run. We cannot possibly have the instrument so set that the voltage may fail to reach the operating voltage when everything is hot, otherwise it would virtually be the same as not having an auto switch at all (although it may work cold). All our switches on cars are therefore set to give a clear margin for this possibility, and that means that the switches are working comparatively readily when everything is cold. Against this we have the fact that usually the starter motor has been used previous to starting and that delays the action of the auto switch to some extent, but if the battery is otherwise fully charged the auto switch would probably cut off the charge comparatively early as compared with when things are hot. We do not mean to say that the auto switch will cut off the battery charge on the horizontal portion of the voltage-time curve of the battery, but only that it will cut it off rather earlier than the final pick-up of the battery voltage at the end of charge. We have sufficient margin to avoid the possibility of cutting off the battery before it begins to gas, as distinct from fully gassing. We put this point up to Messrs. Peto & Radford in the following terms :- Contd. | ||