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 discussing a shift from over-charging to under-charging issues in car batteries and recommending an increase in the charging current.
| Identifier | ExFiles\Box 164\3\ img075 | |
| Date | 2nd December 1937 | |
| PETO & RADFORD. CONTINUATION 2. H.E. West, Esq., 2nd December, 1937. ought to last as long. When we say this, we mean on all cars not only Rolls Royce but others where voltage control has been standardised, but they do not. In the past when a battery came to an end it was 99 times out of 100 due to over-charge, now everything points to the contrary and there are far more cases of trouble through under-charge, and we think that if you make enquiries yourselves you cannot but arrive at the same result. In other words, we think the swing of the pendulum has gone too far in the opposite direction. When a car such as my Bentley is running along in the country, the charging current goes down to about 1 or 2 ampères, or possibly less. This is all very well in theory and it should be quite all right with the battery fully charged and not needing more etc. etc. but in practice it does not seem to work out and it looks as if there is not enough charge, both at the start when the charging rate is higher and putting back what is lost, and subsequently. In fact, the average charging rate is only about a quarter of what it was and in our opinion if it was raised substantially, probably far above what is theoretically required, one would be a long way off over charging or using too much water but one would help the battery not to get into such a discharged condition and if it got very low, one would be helping it to get sufficient charge to bring it up properly, which does not seem to be the case at present. If you read our letters of the past fifteen years, you will find so many complaints of the over charging that we do think we are entitled now perhaps better than anyone, to offer the advice of raising the charging current which we think would confer all round benefits and longer battery life than we look like getting at present. Yours sincerely, GR{George Ratcliffe} Minchin | ||