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).
Laboratory analysis and note on the effects of 'Nemolyt' battery dope.
| Identifier | ExFiles\Box 164\4\ img157 | |
| Date | 12th May 1934 guessed | |
| TECHNICAL NOTE ON "NEMOLYT" BATTERY DOPE. Samples of the above dope were obtained in two grades, one marked SN{Mr Sanderson} "for accumulators for stationary purposes, radio, telephone, telegraph, signalling, etc.", and one FN, "an auxiliary electrolyte, necessary for the treatment of accumulators with Nemolyt.". These two grades were tested in the Laboratory with the following analysis result:- (gm. per 100 c.c.) SN{Mr Sanderson} FN Fixed residue 4.4 4.68 Sulphuric acid 22.24(1.140 s.g.) 0.12 Aluminium sulphate 0.17 0.21 Magnesium sulphate 3.86 4.13 Tartaric acid Appreciable Nil Sp.{Mr Spinney}gr.{George Ratcliffe} at 18°C. 1.171 1.047 Based on this analysis, it will be seen that grade SN{Mr Sanderson} Nemolyt is a solution of magnesium sulphate and tartaric acid together with a trace of aluminium sulphate in dilute sulphuric acid, and that grade FN Nemolyt is a solution of magnesium sulphate in water, containing also a trace of sulphuric acid and aluminium sulphate. It should be noted that the effective acidity of the Nemolyt corresponding to 1.140 sp.{Mr Spinney}g. acid is abnormally high for refilling batteries after discharging as suggested in the instructions, when a final sp.{Mr Spinney}gr.{George Ratcliffe} of approximately 1.080 is reached. The result of this procedure is seen in an end-of-charge acid sp.{Mr Spinney}g. of approximately 1.330, a value which would reduce the life of the normal battery particularly under high temperature conditions. The use of grade FN Nemolyt is restricted to diluting too strong acid in cells to the correct sp.{Mr Spinney}g. and to periodic additions to the electrolyte. In accordance with the printed instructions, two cells of a new fully charged 6-volt XC13 starter battery were discharged, filled with Nemolyt, grade SN{Mr Sanderson}, and re-charged, the third cell being discharged and recharged without changing the acid. Discharges were taken at 7.6 amperes and 200 amperes, with the following results:- | ||