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).
Instructions for the care and first charge of Peto & Radford accumulators.
| Identifier | ExFiles\Box 38\5\ Scan187 | |
| Date | 26th November 1921 guessed | |
| PAGE 1 GENERAL INSTRUCTIONS FOR THE CARE OF PETO & RADFORD ACCUMULATORS. Tops of the batteries should be kept clean, and the terminals protected with vaseline when they have been securely connected up. The vaseline should not be allowed to interfere with the metallic contact between terminals and connections. It is very important that the acid should always be maintained at its correct level by the addition of distilled water, or damage to the plates will result. Never add acid to a battery without obtaining the advice of a battery expert, unless it is known that some of the acid has been spilt or stopped over. Dilute acid of the correct Specific Gravity must then be used. Batteries must always be kept as fully charged as possible, and must never be allowed to remain in a discharged condition. EFFECT OF TEMPERATURE ON SPECIFIC GRAVITY OF ACID.—The figures given for the Specific Gravity of Acid are based on the temperature of the acid being 60° Fahr. At higher temperatures the Specific Gravity of acid is lower than at 60° Fahr. and vice versa, therefore a certain figure must be added to or deducted from the readings obtained at other temperatures to ascertain their equivalent Specific Gravity Values at 60° Fahr. for comparison with figures specified in the instructions as these are based on 60° Fahr. The adjustments tabulated below are for any strength of acid and will give approximately the equivalent Specific Gravities which would be obtained at 60° Fahr. :— Acid at 50° Fahr.—Deduct .004 from readings to obtain equivalent S.G. at 60° Fahr. 55° .002 60° — 65° —Add .002 to readings to obtain equivalent S.G. at 60° Fahr. 70° .004 75° .006 80° .008 85° .010 90° .012 95° .014 100° .015 PAGE 2 INSTRUCTIONS FOR FIRST CHARGE OF PETO & RADFORD ACCUMULATORS. When an accumulator is received in a dry condition it has not been charged, and it will be necessary to fill the cells with acid solution, and charge the accumulator properly before it is put into use. The first charge must be carried out exactly in accordance with the instructions below, otherwise the battery will not work satisfactorily. THE ACID SOLUTION. The acid solution must not be put into the cells until the arrangements for charging are available. The acid mixture consists of pure concentrated Brimstone Sulphuric Acid (Accumulator Acid) diluted with distilled water to a strength or specific gravity of 1.250 at 60° Fahr. This specific gravity is obtained by adding one part of concentrated acid to approximately 4 parts water. Purity and correct strength of the acid mixture are of the greatest importance. The acid must be as specified above. Ordinary commercial sulphuric acid is not suitable as it contains impurities which would be harmful to the accumulator plates. On no account must spring, river, or pump water be used to dilute the acid, as these usually contain impurities, such as iron, lime, etc. MIXING THE ACID.—When mixing, add the acid very slowly to the water; never add the water to the acid, except for the purpose of slight adjustment of the specific gravity after testing with the hydrometer. Heat is produced by the chemical action between the acid and the water, therefore great care should be taken to comply with these instructions. (Diagram 1: A beaker labelled 'WATER' is shown with 'ACID' being poured into it from a flask. A 'WOODEN STICK FOR STIRRING' is in the beaker. The beaker is labelled 'GLASS OR EARTHENWARE UTENSILS.' Below it reads 'STIR THOROUGHLY. Diagram 1.') The mixing vessel must be of glass or earthenware, and the mixture should be well stirred with a wooden stick. Metal vessels must not be used, as all common metals except lead are affected by Sulphuric Acid, which will absorb impurities and cause damage to the battery. After mixing, the solution should be allowed to cool, and the specific gravity read by means of a hydrometer, specially constructed for the purpose. (Diagram 2). (Diagram 2: A hydrometer syringe is shown. It has a 'RUBBER BULB.' The text points to the liquid inside: 'ACID SOLUTION DRAWN INTO BODY OF SYRINGE BY MEANS OF RUBBER BULB.' Another label points to the hydrometer scale: 'SPECIFIC GRAVITY INDICATED BY READING OF HYDROMETER AT THE POINT WHERE IT EMERGES FROM THE SOLUTION.' Below it reads 'Diagram 2.') If the specific gravity is not exactly 1.250, add a little more acid or water as required to correct it before putting into the cells. | ||