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).
Chart recording of a battery discharge test comparing P&R and Exide cells.
| Identifier | ExFiles\Box 54\1\ Scan334 | |
| Date | 30th June 1925 | |
| 7 S4 8 30-6-25 157 S4 Battery 102 lbs 80 a.h. The voltage of the P&R cells were much lower than the Exide cells whilst standing discharged. REGd. TRADE MARK "MEGGER" Average amperes = 6.5 Hours - 19.58 Ampere hours - 62.3 .611 1.80w | ||