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 an accumulator manufacturer discussing battery wear, sludge formation, and longevity.
| Identifier | ExFiles\Box 54\1\ Scan071 | |
| Date | 8th December 1925 | |
| Y4617P Works, Dagenham Dock, Essex TELEPHONE VICTORIA 3667. 5 LINES. PRIVATE BRANCH EXCHANGE. TELEGRAMS CONCENTRATION, SOWEST, LONDON. Manufacturers of P & R Accumulators. Established 1889 PETO & RADFORD Proprietors - Pritchett & Gold and E.P.S. Company Ltd. 50 GROSVENOR GARDENS, LONDON, S.W.1. DIRECTORS: SIR ARCHIBALD C. COLT K.C. GRAHAM MENZIES C.R.N. MINCHIN WILLIAM PETO C.R.D. PRITCHETT T.W. PRITCHETT YOUR REF. OUR REF. M/5. 8th December 1925. E.{Mr Elliott - Chief Engineer} Fowler Clark Esq., Messrs. Rolls Royce Ltd., DERBY. Dear Fowler Clark, Replying to yours of the 2nd inst., the quickest and fairly reliable way that you can tell whether the battery has been overcharged or not is by the amount of sludge at the bottom. If a battery, having hard paste such as ours, has been properly charged and never overcharged you will find that even after it has done a good deal of work there will not be very much sludge, i.e. not very much active material will have been shed from the positive plates. If there is a good deal, as there has been in the case of most of the R.R. batteries examined, then one can say for certain that the battery has been overcharged. Your remark that if the stuff would only keep on the positive plates and the battery reasonably used it would last indefinitely, is interesting, because I suggested only recently to Mr. Preston whether we could not do something to ensure that the material has got to remain on the positive plates. My suggestion amounted to putting the whole plate in some sort of tight fitting bag, but we did not get very far with the idea. With regard to the 6-volt Exide battery you have which is 6 years old, this probably has been properly treated and it will last the time you mention, and we have ourselves numberless instances of batteries lasting a good deal more than 6 years. It is quite possible that in such a battery the positive plates would fall to pieces if the battery were opened up, but even so, as long | ||