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 comparison test report for various car models under cold conditions.
| Identifier | ExFiles\Box 151\3\ scan0366 | |
| Date | 4th February 1938 | |
| -6- Rm {William Robotham - Chief Engineer} /Sym.1/RH. {R. Hollingworth} 4.2.38. BATTERY COMPARISON TESTS ON 28.G.VI AND 5.B.IV. Car. | Type of Battery. | Ignition Volts. | Starter Volts. | Battery Volts. | Starter current. | SP. {Mr Spinney} Gravity of Battery. | Engine R.P.M. ---|---|---|---|---|---|---|--- 5.B.IV | Bentley | 7.3 - 7.5 | 7.5 | 8.75 | 210 | 1260 | 66 " " | Wraith | 6.7 | 6.6 | 8.0 | 270 | 1270 | 53.3 28.G.VI | Wraith | 6.4 | 6.5 | 8.0 | 249 | 1280 | 40 " " | Repeat | 6.3 | 6.1 | 7.5 | 273 | 1265 | 35.5 " " | Bentley | 6.3 | 6.0 | 7.7 | 270 | 1280 | 35.5 " " | Repeat | 6.3 | 6.3 | 7.8 | 264 | 1265 | 40 " " | Phantom III | 7.7 | 7.1 | 9.0 | 285 | 1270 | 50 " " | Repeat | 7.5 | 7.1 | 9.0 | 285 | 1270 | 48 " " | 30 H.P. | 7.5 | 6.8 | 8.5 | 220 | 1275 | 60 30H.P. Production Chassis. | 30 H.P. | 6.8 - 7.0 | 6.3 - 6.5 | 8.0 | 272 | 1265 | 60 The above figures were taken while the engine was being turned over by the starter motor for 15 secs. The batteries were fully charged before each test. Clutch in operation. Cold chamber temp. 8°F. {Mr Friese} Engine oil used - Mobiloil Arctic. Gear box oil used - Motorine C. Temp. of engine oil 9°F. {Mr Friese} | ||