Article reprinted from 'The Motor' magazine detailing the testing of a new design of Tungstone accumulator battery.
| Identifier | ExFiles\Box 35\4\ scan 183 | |
| Date | 26th January 1926 | |
| X. 3830. Reprinted from The Motor January 26, 1926. Testing the Tungstone Battery. New Design of Accumulator Tried Under Very Stringent Conditions. An article describing the results obtained with a very novel type of accumulator. IT will be recalled that the first illustrated description of the very novel Tungstone accumulator was published in The Motor dated December 1st, 1925. We subsequently obtained a 12-volt accumulator of this type for the purpose of making various tests, the rated capacity of this unit being 50 ampere-hours. It was filled with acid, given a thorough charge on the bench, and was then fitted to the running board of one of our staff cars—a 1925 model 10-26 h.p. Singer—the date of fitting being December 20th. For some weeks the battery was used more or less normally, to give it a good start in life, and it was found in the first place that, thanks to the low internal resistance which the method of construction affords, a very heavy current can be obtained, so that even on the coldest mornings the starter-motor will turn the engine at quite a respectable rate of rotation without assistance. In fact, throughout the wintry weather experienced in London towards the end of 1925, the starting handle of the car was never touched, although it was habitually left overnight in an unheated garage built of wood. Early in January a good deal of carburetter trouble was experienced owing to filling up with some defective petrol, which contained a considerable amount of water, intermittent stoppages of the jets being thereby caused. On quite half a dozen occasions the car stopped suddenly in traffic, due to the water, and it was then driven on the self-starter to a convenient point at the kerb—sometimes a matter of 30 yards or 40 yards. Up 1 in 20 on the Self-starter. On another occasion the same trouble occurred after the car had been left standing outside the garage, and it was then driven into the garage on the self-starter for a distance of 12 yards up a slope of about 1 in 20. The vent plugs of the cells were removed from time to time, but the acid level seemed to be well maintained, and, contrary to expectations, the electrolyte did not appear to leak or creep round the edges of the lids of the die-cast cells. During these weeks of normal running the car was left standing for many hours with the lights on, and the amount of charging was only that obtained by comparatively short week-end runs and intermittent traffic work. The charging rate of the Rotax dynamo on the Singer is from 8 amperes to 12 amperes, according to the speed of the engine. On January 11th the car was taken to a level stretch of road in the country, the surface of which was hard and dry at the time. The first gear was engaged and the car was then driven on the self-starter with the engine switched off and turning against compression. A distance of 179 yards was covered, with the motor running continuously, before the car came to a stop, and then, after giving the battery two minutes’ rest, a further distance of 18 yards was negotiated in the same way. With a rest of one minute’s duration between each trial the accumulator then spun the engine successively for 14 secs., 10 secs. and 8 secs., and finally the engine was got going with the starter-motor after a further short rest. Removal of the vent plugs showed the acid to be bubbling, but there was no real frothing and the cells were barely warm. The car was then driven for a distance of about 30 miles over give-and-take roads, with the battery charging at a rate of 8 amps. to 12 amps., the total time being 65 minutes. A circular route was followed, so that at the completion of this charging period the car returned to the start of the former test. The engine was then switched off, and on this occasion a total distance of 245 yards was covered on the self-starter (48 yards farther than before), the accumulator being given two one-minute rests in the course of the trial. It then restarted the engine and the car was driven home. After the test the plates were removed from the cells for inspection, but were not found to be distorted in any way. In view of the fact that it was not convenient to proceed on a long run for the purpose of recharging, the accumulator was taken to W. D. {John DeLooze - Company Secretary} Foster and Co., the well-known Hampstead Road electrical firm, for examination and charging. Removal of the plates showed that these had not become buckled in the slightest degree, the only defect being that the outside negative plate in practically all the cells had lost flakes of paste from perhaps three or four of the diamond-pattern sections of the grid. Only two other defects were noticeable, these being the cracking and deterioration of the thimble insulators which are placed round the terminal studs (where these pass through the lids of the cells), and slight signs of burning and short-circuiting which were noticeable in two or three cases at the edges of the metal containers. In short, it may be said that the accumulator withstood the trial remarkably well. A Brake Test. It was then recharged for 24 hours, following which the cells were placed together on the bench and coupled up to a starter-motor driving a brake, this being part of the standard equipment of W. D. {John DeLooze - Company Secretary} Foster and Co.’s testing shop. The brake tests showed the accumulator to be exceptionally powerful, and it was obvious that no damage had been done by the somewhat brutal way in which it had been treated. As the result of our trial only two criticisms suggested themselves, and a more prolonged test under service conditions will be necessary to ascertain whether the first of these is really justified. In the first place, it would seem that slight leakage of current is liable to occur owing to the fact that die-cast metal containers are employed in place of an insulator, such as ebonite. The second criticism concerns the terminal nuts which are used, a these being of the well-tried and excellent Vislok pattern. The trouble here is that for some obscure reason the average repair man cannot, or will not, understand the principle of these nuts, simple although it is, so that he delights in forcing them on and off with the halves of the nut not in proper register. Damage to the threads of the stud is, of course, very liable to result when this maltreatment occurs. Temple Press Ltd., 7-15, Rosebery Avenue, E.C.1. | ||
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).