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).
Typed letter discussing cold weather vehicle operation, including anti-freeze and battery charging.
| Identifier | ExFiles\Box 59\1\ Scan055 | |
| Date | 21th December 1938 guessed | |
| -2- obtain and try one of these lamps as soon as possible. It is quite likely that under the severest conditions you could make use of two, or even three, of these lamps locked up alight inside your bonnet, and in this way maintain a very useful temperature. In this way you could avoid the inconvenience of having to let out all the water and refill with hot water, provided you can get it, and at the same time charge your water system with one of the dopes which we recommend to be used of an anti-freezing nature, such as Ethylene-glycol, or Prices' Zero Glycerine mixture, which is quite easy to obtain. One charge of this would last probably all the winter. I have discussed the whole question arising out of your battery being charged sufficient when mountaineering. Of course it must be remembered that practically all your running in mountainous districts will be on a gear on which the time of the cutting-in of the dynamo occurs altogether earlier, and in this way a useful charge should be obtained, even when running at low average speeds. In connection with the dynamo battery-charging-control, certain resistances are at some positions of the switching inserted in the field-winding of the dynamo, the special combination in use by us being found entirely suitable for the majority of owners of Rolls-Royce cars. In a special case such as yours, and to meet the conditions which you have described, it might be a very useful thing for you to have the control of a special switch enabling you to cut out such resistances at will so that if you had reason to believe that your battery wanted charging this switch would enable you to obtain a full dynamo output at a time when no lamps were switched on, but in such case we should not be willing to include your dynamo in our ordinary guarantee because you would have the power, if this switch was carelessly used of keeping the dynamo at its increasingly greater output at such | ||