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).
Comparison of modifications between P & R and Exide N.S.I. 6-volt unit cell batteries.
| Identifier | ExFiles\Box 168b\3\ img252 | |
| Date | 3rd January 1930 | |
| X7535P COPY. JD.{J. Draper - Frames}48. 3.1.30. X7535'E.{Mr Elliott - Chief Engineer} X.7535. P & R and EXIDE N.S.I. BATTERY (224) ------------------------------------ This battery, a the cells of which, compared with the present standard P & R and Exide 6-volt unit cells, contain the following minor modifications :- P & R cells. New type of moulded vent with larger thread like Exide standard. [Handwritten: Full-way ebonite separators not less than .4mm thick] Exide cells. All plates less wide for greater side clearance. Positive plates less high for greater top clearance from negative strap. Also negative strap .100 higher. has now completed its first charge and has been discharged for the first time through a constant external resistance of 1.80 w. and gave 62.4 ampere hours (Discharge 1). The Exide cells shewed positive weakness The P & R has a greater capacity than the Exide, but this may be expected to a certain extent because the active area of the Exide plates is rather smaller than the P & R.{Sir Henry Royce} Being less high they give a greater clearance between the top of the positive plates and the underside of the negative strap. GJ. | ||