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 charging, capacity tests, and cell construction options.
| Identifier | ExFiles\Box 38\5\ Scan039 | |
| Date | 15th April 1919 | |
| X. 3398 Manufacturers of P. & R.{Sir Henry Royce} Accumulators. Established 1889. Victoria & Greville Works, Ashtead, Surrey. THE NEW PETO & RADFORD ACCUMULATOR CO LTD Electrical Engineers MANAGING DIRECTORS WILLIAM PETO M.I.E.E. G.R.N.MINCHIN M.A. 12, HEDDON STREET REGENT STREET LONDON W TELEPHONE REGENT 2576 TELEGRAMS "CONCENTRATION REG. LONDON" REF. M/C.154 15th April, 1919. Messrs. Rolls-Royce, Ltd., Nightingale Road, DERBY. Dear Sir, For the attention of Mr. Fowler Clark. We thank you for your letter of the 12th inst ref EFC1/AT re lighting and starting batteries and specification attached. Since our last letter we have spoken to our chief tester at our works and find that we never get the full output until a battery has been charged at a fairly high rate and started with the acid at about 1200 to 1220. If the acid is put in at about 1260/1300 for the first charge at the end of even a long charge there is very little in the battery. We are making tests on a recording ammeter of a nine plate cell, exactly similar to those you have and will send you the curves in due course. In the meantime we shall be very interested to see whether you get the full capacity from your tests. In clause 6 of the specification you refer to the accessibility and ease of replacement of a single cell. With regard to this, do you like all the cells sealed in all over like our ebonite sample, or separate cells just stuck together with the lids not joined in any way except by the cell to cell connections or entirely separate cells in a crate with wood or rubber lining between each cell. We have made up batteries in all 3 ways, but for strength and resistance to vibration (especially with ebonite which is more or less brittle) we have found the first named method to be the strongest though of course, it does make the removal of a single cell rather difficult. However, in our opinion, if a single cell does go wrong and a man takes it out, the remainder of his battery is of no use to him and he might as well return the whole thing. Besides, if one cell goes wrong, this may be due to causes coming from another and it is as well for the manufacturer to inspect the whole battery. We can work to whichever scheme you prefer and would be glad to hear which you favour. On receipt of your reply we can rapidly make up the next sample. Re B.E.A.M.A. Curve, we regret we have not a spare one by us, but for reference, the figures are as follows:- | ||