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 performance tests, comparing complete starts and failures for four different batteries.
| Identifier | ExFiles\Box 41\2\ Scan094 | |
| Date | 11th March 1918 | |
| Sheet #2 COMPLETE STARTS MARKED X FAILURE TO START MARKED - March 11, 1918. Charging Eight Amperes, Starting Six Times per Hour Fifteen Seconds For Each Start. BATTERY NO.1 BATTERY NO.2 BATTERY NO.3 BATTERY NO.4 X X X X X X X X X X X X - X X X - X X X - X X X - X X X - X X X - X X X X Chart shows that battery No. 1 Willard failed after three starts, and that battery No. 2 failed after eight starts, probably due to the fact that they were in stock for sometime and didi not take their charge properly. All batteries were then p ut on charge at 10 amp. and brough up to 2.5 volts per cell after which the electrolyte was equalised by mixing the solution from all the cells. March 13th, 1918. The Batteries were then put on charge at 10 amp. and used at the rate of 6-15 second starts per Hr. Starter drawing 115 amp. After making eight starts, both Willards had weakened considerably showing approximately 50 points less on hydrometer than the Multiple batteries. After twenty starts the amperage drawn by starter had reduced to 105 probably due to motor freesing up. At the twenty six start, spark plugs were put in motor which ranthe amperage drawn by the starting motor up to 350 and would not turn motor over on any battery. Spark plugs were taken out reducing the amperage used to105. At this point a reading was made of the batteries showing that No. 1 Willard was practically run dwon only reading 110 on hydrometer. No. 2 Willard reading 1150, and bother Multiple batteries standing at 1300 which shows slightly over charged. Batteries were than used for seven more starts when both Willards failed, leaving both Multiple batteries standing fully charged. Batteries were put on charge over night and part of next day until all were equally charged and voltage and hydrometer readings were alike. | ||