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).
Test report on a National RRN.11 battery with modified negative grids.
| Identifier | ExFiles\Box 58\3\ Scan192 | |
| Date | 17th November 1930 | |
| COPY. JD {J. Draper - Frames} 1114. NATIONAL RRN.11. BATTERY (238) WITH MODIFIED NEGATIVE GRIDS. This battery has the modified negative grids as suggested by the National Accumulator Co. designed to give a lower maximum sustained P.D. on charge than the standard battery. It was received dry on 17.11.30 and given its first charge and discharge. Tests were then made on the charging P.D. at 50°F. {Mr Friese} (10°C.) when charging at 0 to 12 amperes. The P.D. was found to be higher than standard by 0.15 to 0.20 volts (per 6-volt unit). Similar results were obtained at 75°F. {Mr Friese} (24°C.) i.e. higher P.D. than standard. It was thought that this was probably due to the battery being new and it was decided to put the battery through a series of charges and discharges to make sure the plates were fully developed. After this treatment frothing took place on full charge and the acid was changed to overcome this. Further tests have shown no improvement after this treatment. The cadmium shows a higher reading on the positive than standard and an identical negative reading with the standard. From the above it would seem that altering the grid of the negative plates has changed the characteristic of the positive plates in some way. EFC {E. Fowler Clarke - Electrical Engineer} /GJ. | ||