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).
Battery cell leakage, electrolytic connections, and testing methods for 4-volt accumulators.
| Identifier | ExFiles\Box 35\1\ scan 115 | |
| Date | 28th April 1917 | |
| H.H. & Co., (L.D. S.D. 408. 28-4-17.) Bm. 2/156/13. Contd. -3- EFCL/T5.2.19. In this case again, the extreme terminals are side by side on one of the blocks and leakage during standing, might be considerable, if there is any acid moisture on the top of the cells. We consider that in any battery, every cell should be made up independently, and afterwards the cells stuck together and connected to one another. In our experience of 4-volt portable accumulators, we have over and over again come across cases in which there has been an electrolytic connection between one cell and another, sometimes due to the forces which the expanding plates exert upon the celluloid. We have always tested for such a connection by removing the series connection between the two cells and applying a difference of potential of about 50 volts between cell and cell. (through a lamp). If any current flows, we know there is an electrolytic connection, if none, we know the insulation is sufficiently good. The symptoms of this on a 4-volt accumulator are invariably that the accumulator will not maintain its 4 volts for long, butwill always maintain two volts (two volts on one cell but none on the other). If, however, the series connection is removed immediately after charging, we have in practically all cases, found that each cell will individually keep up its voltage. Where it is impossible to sever the connections between the cells composing the battery, such a defect may exist and cause trouble without one being able to have any means of proving that it is due to this. Going back to the Lucas battery, the main terminals are fitted with leaden pieces to which to sweat the cables. Two pairs of these are provided, a large pair for the heavy Contd | ||