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).
Guidance on battery acid specific gravity for different climates and battery charging procedures.
| Identifier | ExFiles\Box 139\3\ scan0203 | |
| Date | 14th November 1938 guessed | |
| 3. Acid gravity figures are taken by means of an hydrometer. TABLE DATA: Column Header: Specific Gravity of Sulphuric Acid Solution (Corrected to at 60°F.{Mr Friese} 70°F) Row 1: Temperate Climate - Filling-in for first charge: 1.340 - Fully charged: 1.280 (1.270 - 1.285) - Fully discharged: 1.110 (strikethrough) 1.150 (Approx.) Row 2: Tropical Climate (i.e. where the temperature is frequently 90° F.{Mr Friese} or over) - Filling-in for first charge: 1.260 - Fully charged: 1.210 (1.200 - 1.215) - Fully discharged: 1.100 (strikethrough) 1.080 (Approx.) CHARGING. The output of the generator on the car is controlled so as to vary with the state of charge of the battery. Over-charging the battery is thus automatically avoided. The generator will, under ordinary running conditions, provide enough current to ensure correct recharging of the battery, but in special cases, e.g. when the car is frequently standing with the lights on and daylight running is of short duration, it may be necessary to take the battery off the car from time to time for a bench recharge. This recharge can be done by any well equipped garage or else by a service agent or battery depot. In cases where running conditions result in the battery only being slightly undercharged it should not be necessary to remove it from the car for a bench recharge, because it can be charged whilst still in position on the car by utilising the charging socket in the switchboard on the dash. | ||