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 discussing the experimental testing of production batteries and their charging characteristics.
| Identifier | ExFiles\Box 54\1\ Scan106 | |
| Date | 7th July 1936 | |
| X4617P EFCL/T. 7th July, 1936. Messrs. Peto & Radford, 50, Grosvenor Gardens, London, S.W.1. For the attention of Mr. G.R.N.Minchin. Y8780 Dear Sirs, Thank you for your letter of yesterday's date. Perhaps there is not sufficient justification for obtaining one of your latest production batteries for experimental test solely for the purpose of confirming the P.D. on charge, and I think we must accept your figure of 16.2 volts for the six cells charging at 12 amperes. This shews actually a little lower than the figure for the Exide battery at the same current, but as you say your curve is flattened, your figure might be somewhat higher at lower currents. We are glad to see that Mr. Preston is of the opinion that the tapering charge is equally effective in charging the battery in spite of the fact that the true E.M.F. of the battery is not raised to its highest possible figure. As a matter of fact we have already made a test on the output capacity of a battery charged in this manner as compared with that when charged in the more ordinary way, and we have found the capacity to be the same, but other tests will be made in confirmation. For the purpose we charged through an invariable resistance of .25 ohm at a maintained P.D. across the outer terminals of 17 volts. This must give the Ab characteristic at the battery terminals. 'ontd. | ||