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).
From EFC to AJB detailing the disadvantages and advantages of the Tungstone Battery.
| Identifier | ExFiles\Box 35\4\ scan 177 | |
| Date | 27th January 1926 | |
| 13830 W/S. EFC1/T27.1.26. To AJB. from EFC. X. 3330 - TUNGSTONE BATTERY. Answering your H/AJB3/H26.1.26, the first big disadvantage of the Tungstone battery is its great weight-capacity ratio, which would be 30 to 35% larger than in our present standard batteries, a second disadvantage being the large dimensions, largely due to the fact that the metal cell cases must be separated from one another. A third disadvantage would be the electrical leakage which would take place across the cell lids. Although it may be argued that a single cell does not leak electrically because of the charging effect of the leak current on the metal surfaces involved, nevertheless our experience indicates that it can scarcely be doubted that cells do leak in this manner for various good reasons which we can advance. It is therefore of nearly as much importance for a single cell to have a leakage path of as high a resistance as is practically possible, as it is for two or more cells in series. An advantage of this type of cell might be the reduced high rate discharge resistance due to the absence of separators. Also, if the makers' claim be correct, the fact that it will stand any amount of overcharging, without really being adversely affected. A battery which would, for a period of several years, behave like a water tank which, whilst having a definite and known capacity, suffers no harm due to an overflow, is what we want, but I very much doubt whether this would be the case to a materially greater extent with the Tungstone battery. We had already decided that it would not serve any useful purpose at the moment to have a complete battery, but we have had a single cell for examination and test for nearly a month now, and shall be making observations on the performance to see whether the Makers' claims are justified. Thank you for sending the booklet, though I have had one of these previously. EFC. | ||