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 Exide and Edison accumulator cells regarding weight per amp hour and voltage variation.
| Identifier | ExFiles\Box 1\7\ B001_X15 20 46 50 59-page230 | |
| Date | 18th July 1913 | |
| X 50 Wor{Arthur Wormald - General Works Manager}/SM3/L18713. X 50 X 607 Re Exide Cells X.607 and Edison Cells X.50 R.{Sir Henry Royce} 18-7-13. In reply to Mr Royce's memo FHR6/C25613, we have obtained from Mr Ellis the following information. Re Accumulators. Weight per amp. hour (actual) Edisons 12 volts Discharging rate 8 amps=.81 lbs " " " " " 1 " =.55 " Exides 4 " " " 1 " =.38 " " " " " " 3 " =.33 " The weight of a 12 volt Exide will be 3 times the weight of the 4 volts. We have no Exides for heavy discharge but Mr Nadin states that there is a set on order for lighting work. Variation of Voltage. Discharge. Edisons 12 volts. 12.2 volts at the commencement of discharge after fully charging. 10.8 volts at which the cell must be recharged. 1.4 volts variation on 12.2 V = 11.4% | ||