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).
Technical evaluation of battery components, capacity, and a comparison between different battery models.
| Identifier | WestWitteringFiles\J\November1922\ Scan82 | |
| Date | 15th November 1922 | |
| Contd. -2- EFC/L/T15.11.22. (5) Both positive and negative grids are fitted with pairs of feet in such a manner that the positive and negative plate sections are independently supported by two pairs of ribs moulded in the cell case, thus short circuiting by accumulation of sediment at the points of support of the plates is avoided. (6) The separators are of wood but much thicker than those used in the Exide cells and ribbed on both sides in contact with the plates. Owing to increased thickness of plates and separators short circuiting by buckling is nearly impossible. (7) For the cell cases the P & R patent material known as Dagenite is used, which we are satisfied cannot possible crack or leak under any conditions of service. It is a fact we have verified that the cell cases can be dropped on quite a hard floor without being cracked. The material of these cell cases has a bituminous base. (8) The cells are fitted with the P & R porcelain vent which has anti-splash chamber and coned vent hole to break up bubbles. The vent is in addition fitted with feet which rest on the top of the separators between the plates and hold these down, also minimising the amount of spraying with which the vent has to deal. (9) The lighting capacity of 50 ampere-hours claimed by the makers for these batteries is just about correct according to our own discharge tests on these. Actually the low rate discharges have been taken through a constant external resistance of 1.75 ohms and have shown very consistently at this rate capacities of 46.5 ampere-hours; this converted to the 10 hour rate comes out almost exactly at 50. (10) On the high rate discharge tests through a constant external resistance of .100 ohm they have also shown that they are capable of maintaining a current in excess in all cases of 100 amperes for a period of five minutes, the initial current being in the neighbourhood of 105 amperes. These results are a little better than those for the C.A.V. 12 KR2 and Exide 6 KR3 which will be the alternative standards. The weight of the P & R battery is 80 lbs. (most recent battery) as compared with 66 lbs. for the C.A.V. and 70 lbs. for the Exide. The plates are, of course, thicker and it is considered certain that the life will be materially longer. (11) Taking all things into consideration it is extremely doubtful whether, in the space provided, a more suitable battery for the Gosling could be made, a battery utilising every cu. in. of available space with like efficiency. Contd. | ||