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).
Article describing a dashboard-mounted ampere-hour meter designed to measure a vehicle's battery charge.
| Identifier | ExFiles\Box 54\2\ Scan217 | |
| Date | 13th December 1927 | |
| The Motor 1000 December 13, 1927. Measuring the Contents of the Battery. A Much-needed Dashboard-fitting Device Designed for this Purpose. ALTHOUGH the electrical equipment of cars has reached a very high standard of efficiency and reliability, there are still many things wanted before an ideal can be claimed to have been attained. One in particular is an electrical dashboard-fitting device which will record the contents of the battery in much the same way as the petrol gauge records those of the petrol tank, giving the motorist an indication at a glance of the "amount of current" (to express it colloquially) that the battery contains. The urgent need for such a device was first aired in the issue of The Motor dated March 15th, and it aroused considerable interest, there being published in several following issues a number of letters received from readers interested in the idea. In many quarters it was considered an impracticable thing to devise such a gauge, but that this is possible is shown in a neat instrument now marketed by the Central Manufacturing Co., of Crown Works, Birmingham Road, Walsall. This is known as a battery capacity ampere-hour meter, its purpose being to give an indication of the charge condition of the battery. Design of the Device. The device consists of a high-grade moving coil meter, and the scale, across which a pointer moves, in addition to being calibrated in ampere-hours, is split up into three coloured divisions, red, yellow and blue being employed to show low charge, medium charge and full charge. When taking readings with the instrument the dynamo must obviously be switched off. The "low" portion of the scale is marked in red with an indicating mark showing that the battery is discharged, but at the extreme end of the blue scale is another red mark showing that the battery is fully charged. When this reading is obtained the car should, of course, be run with the dynamo switched off. Naturally, the red indications are fixed according to the battery manufacturers' instructions for electro-chemical reasons, and they vary with different types. Therefore the necessity for stating clearly the make and type number of the battery fitted to the car when ordering one of these devices is obvious. Not only will this meter give the motorist warning when the condition of his battery is poor, but it will also indicate when the battery is fully charged, at which point the dynamo should be switched off so that no further current is supplied, as to continue charging a battery which is already fully loaded will do considerable damage, the paste in the plates being affected and crumbling away after a time. The fact that the battery is being charged is shown also, the pointer at such a time moving as the capacity increases. Easily Fitted. No trouble is involved in installing the instrument, it being only necessary to make connection across the terminals of the battery, which can be done through the switchbox or junction box. [Image of two gauges] Text on left gauge: BATTERY CAPACITY AMPERE-HOURS, OFF, CHARGING, DISCHARGING Text on right gauge: ACCUMULATOR CAPACITY INDICATOR, OFF, EMPTY, FULL On the left is shown the battery capacity ampere-hour meter, the instrument on the right being a less expensive accumulator capacity indicator. When it is desired to know the correct ampere-hour capacity of the battery, the user must make sure that the dynamo is not charging and then switch on momentarily all the car lights in order to put a load upon the cells. Should the pointer gradually fall instead of remaining stationary at the charged position after the lights have been switched on, this, it is stated, is an indication that the battery is either not in good condition or that the plates are not covered with acid of the correct density as specified by the makers. A press switch can be fitted in the circuit if desired, putting a special shunt load across the battery, although the manufacturers of the device consider it more useful if left in circuit continually, there being practically no load upon the battery in this circumstance, as the consumption of the device is only six milliamps. The price of this device is 30s. Less Expensive Model. There is a cheaper model of the device in the form of an accumulator capacity indicator only. It is similar to the above, but without the calibration in ampere-hours on the yellow portion of the scale. This is listed at 12s. We have received samples of these instruments and are carrying out tests of them, reports of which will be given in The Motor at a little later date. With regard to the fitting in the instrument board, if there is not sufficient room for this, special clips can be supplied to suit either instrument to facilitate installing the device in a convenient position. In addition to their use for the car battery, they can, of course, also be used when charging or testing wireless batteries, it being possible to calibrate them to any number of cells. Two Cleaning Preparations. A Polishing Cloth. WE have recently tried a polishing cloth for cleaning any type of metal, such as silver, nickel, brass, copper, aluminium and so on, and the results were quite good. The cloth is specially treated, and all that it is necessary to do is to rub down the part to be polished until the desired sheen is obtained. We had this cloth from G. {Mr Griffiths - Chief Accountant / Mr Gnapp} Atherton and Co., (Dept M.O.), 17, New Brown Street, Manchester, who markets the cloths at 1s. 3d. each. They can be obtained also from garages, stores and so on. A Good Liquid Hand Cleanser. ONE of the many preparations which have been submitted to us for test recently is a hand cleanser known as Gre-Sol. This we have tried, and find that it is effective, and it is also pleasant to use. The preparation is in the form of a jelly, and when first applied to the hands will be found to cover them completely with a thin film of the preparation, which, after a moment or two will become tacky; with the addition of a little cold water, this will form a lather all over the hands when they are rubbed together. Rinsing them in cold water afterwards will completely remove all dirt. It will not harm the most delicate skins, as its action is simply to emulsify any substance which may have found its way into the pores. | ||