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).
Comparative analysis of a standard battery versus a Lucas battery, detailing performance, capacity, and lifespan.
| Identifier | ExFiles\Box 164\2\ img048 | |
| Date | 20th May 1940 | |
| - 3 - Cont'd.{John DeLooze - Company Secretary} Rm{William Robotham - Chief Engineer}/RC.{R. Childs}3/ML.20.5.40. Total number Cycles at Cycles at of Cycles. low Rate. high Rate. Standard 195 160 35 Lucas 175 140 35 It will be seen from observations 1, 2 and 3, that while the Lucas battery is practically the same in size as the standard, it is heavier and has a larger capacity. This suggests that the plates have been made thicker at the expense of acid space, and possibly separator strength. Support for this is shown in 4, where the increase in internal resistance, due to the lower temperature, is much greater than with the standard. The rate of diffusion of acid, in the plate, is reduced with lower temperatures, and it seems that with a larger volume of plate, and a smaller volume of acid, the result is more marked. Summarising these results we can say that, for the same size, the Lucas battery is heavier than the standard, and not so good at starting under cold-weather conditions. These are two important points. It has a somewhat larger capacity, and would probably turn the engine a little faster in a normal or warmed-up condition. These advantages, however, are relatively unimportant. Finally, from 6, the Lucas battery was found to have about 10% shorter life than the standard. We think that, from the point of view of weight, and starting under low-temperature conditions, alone, Lucas batteries of the type tested, would be unsuitable for the car. This is particularly so when we remember, that the margin of safety in respect of starting when cold, is small even with the standard battery. ----------- Rm{William Robotham - Chief Engineer}/RC.{R. Childs} | ||