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).
List of battery types for 40/50 HP and 20 HP car models.
| Identifier | ExFiles\Box 54\2\ Scan067 | |
| Date | 16th November 1925 | |
| Y467 16.11.25. RE BATTERIES. 40/50 HP. Exide 6RH {R. Hollingworth} 5. P & R. {Sir Henry Royce} RR.11. 20 HP. Exide 6XL3/4. P & R. {Sir Henry Royce} TBD.7. EFC. {E. Fowler Clarke - Electrical Engineer} | ||