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).
Simple indicator device to prevent over-charging car accumulators.
| Identifier | ExFiles\Box 59\1\ Scan118 | |
| Date | 18th February 1927 | |
| TO EFC. } FROM R.{Sir Henry Royce} (At Le CanadelHenry Royce's French residence.) CAR ACCUMULATORS - OVER-CHARGING ETC. X4008 R1/M15.2.27. DESPATCHED FROM WW. 18.2.27. X.4008 X 4040. For a very long time there has been anxiety to know when the battery is charged. EFC. has produced I understand the Midgeley device in another form which reduces the rate of charge when the volts rise to a certain figure. I am not much in favour of such a device, because - (1) of the increased complication of an already extremely unavoidably complicated system on a car (2) the difficulty of getting such a device to act with sufficient accuracy. I should like Mr. Northey to give his opinion on this sch. As another scheme I suggested to Mr. Minchin a very simple scheme of closing with unventilated plug one cell, and connecting by rubber or other small piping to a simple indicator (upon the dash) of say 1/8" dia. glass tube with a small nozzle at the bottom for the gas to issue from; it is arranged as a syphon and the glass tube half filled with water or other liquid, coloured or clear, so that when the control cell gasses a stream of bubbles pass through the water. This has been made by Peto & Radford and works well on my 7-EX. So far as I can see it should only cost a few shillings and tells the driver when his battery is charged - three advantages: (1) If it is full (it removes the anxiety about having any charge.) (2) When to stop (prevent destruction and loss of water by overcharging.) (3) It saves nearly all the wear on dynamo commutator and brushes when not charging. We find it worth its place and cost. Is it worth a patent - at least a provisional in England? It is not necessary to see it at night. Will Mr. Northey and EFC. give us their opinions? R.{Sir Henry Royce} | ||