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).
The charging systems and batteries for the 20 HP and 40/50 HP models, including undercharging complaints.
Identifier | ExFiles\Box 54\1\ Scan064 | |
Date | 2nd December 1925 guessed | |
-4- Contd. Re the 20 HP. system, comparing the relative capacities with the relative charging rates, we agree that relatively the 20 HP. battery is not so large, but whereas we have been allowed to increase the 40/50, the 20 HP. was the maximum size that Mr. Royce could possibly allow in the rear of frame. The smaller car requires very nearly as much current, for lights, etc., as the larger, and really should have a battery nearly as large. That does not, however, apply to the dynamo; the function of the larger dynamo on the larger car is not so much to give a larger output, as to give the same output at a lower speed. As you point out, we have only one ampere more on the peak on the 40/50 as compared with the peak on the 20 HP. and this we consider about right, and we agree that, strictly speaking, the batteries should be in this proportion. Therefore we may expect to observe that the charging voltage on the 20 HP. except for the fact that the 20 HP. P & R battery appears to be relatively lower in charging resistance, may be even greater than on the 40/50. We are at the present moment doing bench experiments on the 20 HP. dynamo with its own chassis wiring and batteries, in order to compare the results with those I have now given you for the 40/50. I have previously noted, when taking cars on the road, with a voltmeter, that in a general way, the voltage on the 20 HP. system was higher. Still referring to the 20 HP. system, I find on enquiry in the Repair Dept. that we have complaints of undercharging on this system, and that in the particular case of one complaint, the output curve for some reason or other was about 1 ampere less on the peak than our minimum specified output. Within the last week or so a our Mr. Chandler has brought me along two definite cases of undercharging on the 20 HP. He will let me know of any further cases that come to his notice. I do not, however, know of any cases on the New PhantomCodename for PHANTOM I, but it is rather too early for that anyway. We have, however, had a list of [customers] complaints generally on the New PhantomCodename for PHANTOM I, and as regards the electrical system there is practically nothing. There is one complaint only of the dynamo - I do not know the details - and no complaints at all of batteries. I xxx think alround that our specified curves are about right and Mas previously stated, when I am satisfied that I am not going below these curves, I am prepared to reduce the output so far. Contd. | ||