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).
Technical justification for using the more expensive TBD7E battery over cheaper alternatives for the 20/25HP model.
| Identifier | ExFiles\Box 58\3\ Scan170 | |
| Date | 4th February 1931 | |
| 67.6. X. 6104. 4-2-31 JD. {J. Draper - Frames} 115. X4642 20/25HP Battery. With reference to DA {Bernard Day - Chassis Design} 3/M23-1-31 we agree that the TBD7E Battery is more expensive than other batteries of similar capacities & dimensions we do not think any economy would be effected by the using of a cheaper battery for various definite reasons. Having a greater capacity battery in a similar space means overcrowding of the plates which results in less acid room which is a great detriment to starter batteries. Having less acid room means more frequent attention needed for topping up etc, it also involves using a higher SG {Arthur F. Sidgreaves - MD} acid otherwise the discharged SG {Arthur F. Sidgreaves - MD} would be too low. High SG {Arthur F. Sidgreaves - MD} acid quickly rots the separators making them inefficient. In these cheaper batteries no wood (cont'd) | ||