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 accumulator manufacturer Peto & Radford discussing options for a lighter battery for a Bentley chassis.
| Identifier | ExFiles\Box 58\4\ Scan229 | |
| Date | 18th December 1935 | |
| Works, Dagenham Dock, Essex TELEPHONE SLOANE 7164. 5 LINES PRIVATE BRANCH EXCHANGE TELEGRAMS CONCENTRATION, SOWEST, LONDON. Manufacturers of Accumulators for over 50 years. PETO & RADFORD Proprietors - Pritchett & Gold and E.P.S. Company Ltd. 50 GROSVENOR GARDENS, LONDON. S.W.1. YOUR REF........... OUR REF M/5. Handwritten: Car batteries 18th December, 1935. Messrs. Rolls-Royce, Ltd., DERBY. Handwritten: WST For the attention of Mr. West. Dear Sirs, Further to the conversation the writer had with Mr. West and Mr. Rowbotham, as you requested we did see what we could do about offering a lighter battery for the Bentley chassis without affecting the performance very much. Firstly, we might point out that when Mr. Rowbotham referred to the lighter weights of the American 6-volt batteries, he was perhaps overlooking the fact that with 6-volts, heavier cables, switchgear, starter and dynamo (with more copper in them) have to be employed and although we do not know how much the saving in battery weight this offsets, it must be a good deal so the total weight of the 12-volt electrical equipment should not be much more than the 6-volt American. The present battery 6.BDH.9-S weighs with cover, dry, 59¼ lbs. and has a capacity at the 20-hour rate of 58 ampere hours. We could put in-to a size smaller container (which would be 1.11/16" less in length) a battery having a 9-plate section with thinner plates but taller, weighing with cover 47¼ lbs. and having a capacity of 54 ampere hours. The capacity at the 20-hour rate is about 3% or 4% less but the present charging dynamo arrangements would take care of its not being over-charged which would be the danger in the past and the chief drawback that there was less margin if the car was left standing about with lights and then called upon to start. For the actual starting effort however, the plates, being slightly greater in surface would be greater in the proportion of 1.1 to 1 so there would be more margin for starting although we understand you can do | ||