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).
Letter from Peto & Radford detailing improvements to batteries and recommending specific models.
| Identifier | ExFiles\Box 38\5\ Scan153 | |
| Date | 8th October 1921 | |
| PETO & RADFORD. CONTINUATION 3. Messrs. Rolls Royce Ltd., 8th October 1921. that we have introduced during the last twelve months which tend to make this battery still better. 1. The thickness of the positive plate has been increased from 1/8" to 5/32" adding mechanical strength and increased capacity. 2. We have now produced a basket grid with the ribs tapering inside thus locking the material and preventing the possibility of pellets falling out. Mr. Birkitt took one or two samples of these new grids. 3. The plates have small feet for resting on the bottom rests of the cell and this secures the independent support of the positive and negative plates and greatly reduces the chance of short circuiting at these points. 4. The separators have ribs on each side thus giving better circulation of acid and increasing by 50% the amount of free acid. We consider there is not sufficient acid in the American type (we have to produce it because of the replacement business where dimensions have to be kept to). 5. The separators are now cut so as to ensure having a solid rib at each end. If the edge of the separator happens to be the thin web it makes it easier for a curling plate to short circuit on to its neighbour. 6. The cell containers are now made of material which will not crack or split and leakage is almost impossible. The H.D.E. type of battery with the above improvements is now called by us "The Bull Dog" battery and we believe it represents the best battery at present on the market. For the 40/50 H.P. car we recommend "The Bull Dog" type B.D.11 which has a capacity of about 65 to 70 ampere hours. For the small 20 H.P. experimental car, about which you wrote us recently, we suggest the Bull Dog type B.D.7, 45 to 48 ampere hour capacity. If you are satisfied with the report on the H.D.E.13, we | ||