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).
Guide on battery maintenance, fault finding, and the use of associated monitoring instruments.
| Identifier | ExFiles\Box 54\2\ Scan232 | |
| Date | 18th June 1928 guessed | |
| of the same specific gravity as stated on the Battery. On an old Battery it is possible to obtain the correct charged specific gravity of acid, but it would not contain the full stated capacity. When a Battery has been subjected to a heavy discharge the Instrument would immediately show a drop and then recover in a very short time. This is due to the excessive discharge taken momentarily from the Battery, but if after a short time, when the Battery has settled, the testing load equivalent to a 10 hour rate is connected across the Battery, these Instruments will indicate definitely how much charge has been taken from it, and from observations under actual charge conditions, it takes very little time to put back the used charge, (this, of course, depends upon the amount of current consumed when pressing the Starter Switch and the rate of charge that the dynamo is generating). The owner is then able to put exactly the amount of charge into the Battery that has been used previously. From our prolonged tests, we can definitely state that our Battery Ampere Hour Meters and Indicators will also give a reasonably accurate reading when a Battery has been overcharged and is not in first-class condition. If an old Battery has been charged at the normal rate and the pointer has reached the fully charged position, after allowing the Battery to settle, the lamps are switched on or a testing load is connected across it, the Instrument will indicate how much the Battery has deteriorated. If it is impossible, after charging the stated time, for the pointer to reach the fully charged position, this is an indication that the Battery is either being charged below normal or that Battery requires immediate attention. From observations of our Instruments, fitted on a car under actual working conditions, they definitely indicate over a scale area the amount of charge that the Battery will retain. For example, when a Battery has deteriorated to say 40% of its original capacity, the length of time for recharging a Battery in this condition may be one hour. A further prolonged charge of say 5-7 hours (with the object of increasing its capacity) will not be retained by the Battery. Although a Battery may have deteriorated in its capacity, it will still be able to respond to its work, but will require charging more frequently, and these Instruments are just as reliable when fitted in circuit with a Battery in this condition, for indicating the state of charge, as when connected to a new Battery. If these Instruments are fitted when the Battery is new, the risk of over-charging is reduced, and it enables the owner to obtain 100% efficiency from a Battery. Below we give a few of the faults which have been revealed through the use of these instruments. Battery terminal corroded, causing leakage to case. Broken cell partition causing leakage from one cell to another. Acid density incorrect. Plates not covered with Electrolyte. Piece of copper wire connecting cell to case causing leakage, etc. Re the fitting of a Press Switch in circuit. Several makers state that a little drain from a Battery is better than allowing it to lie idle, as it keeps a Battery in good condition. The Ampere Hour Meters consume only 6 milliamps, and as the discharge position of a Battery is indicated on these Instruments, when the pointer reaches this, it is a warning that the Battery needs attention. In the case of the Battery Capacity Indicators, these consume 25 milliamps, and unless the Battery is being charged frequently, it is advisable to fit a switch. These Instruments can be supplied to suit any size, capacity battery, or number of cells in various patterns, Nickle-plated or Black finish. Patents pending in U.S.A., France, Canada, Germany, Italy and all principal countries. | ||