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).
Instructions for the first charge of Peto & Radford accumulators.
| Identifier | ExFiles\Box 38\5\ Scan188 | |
| Date | 2nd December 1921 guessed | |
| INSTRUCTIONS FOR FIRST CHARGE OF PETO & RADFORD ACCUMULATORS. FILLING THE CELLS.—To fill the cells remove the vent plugs or caps and fill each compartment, using a glass funnel and a small earthenware or glass jug for the purpose, or similar convenient method avoiding the use of metal utensils. Each cell should be filled up until the acid solution has covered the plates by about ½ inch, and the battery allowed to stand for 3 hours before commencing the first charge. The vent plugs or caps should not be replaced until after the first charge is completed. THE FIRST CHARGE. The first charge must be commenced 3 hours after filling the cells with the acid solution, but before connecting up inspect the acid level and add more acid solution if the plates have absorbed sufficient to reduce the level below the tops of the plates. CONNECTING UP TO CHARGING CIRCUIT.—Connect the positive terminal of the battery to the positive terminal of the direct current electricity supply, and the negative terminal of the battery, through a suitable resistance, to the negative terminal of the supply. This should be done by means of a suitable switchboard, on which meters, resistances, and switches are provided to enable the current to be regulated. Diagram 3. Connection to NEGATIVE terminal of supply through a suitable resistance. Connection to POSITIVE terminal of supply. When a number of accumulators, having equal charging rates, have to be charged, they can be connected together in series, the positive of the first battery being joined to the negative of the second battery and the positive of the second battery to the negative of the third, and so on, leaving the negative of the first battery and the positive of the last battery for connection to the supply as described above for single batteries, and as shown on the Diagram 4 on the opposite page. The number of batteries which can be charged in series depends on the voltage of the supply circuit, but it can be roughly estimated that the number of two volt cells that can be put on any circuit will be the total voltage of the circuit divided by three. This is the most economical method of charging as it reduces the amount of resistance required, and saves waste of current. The arrangement of the circuit should be carried out by an Electrician. Diagram 4. CONNECT TO NEGATIVE TERMINAL OF SUPPLY THROUGH A RESISTANCE. CONNECT TO POSITIVE TERMINAL OF SUPPLY. CHARGING CURRENT.—For the first charge the strength of the current in amperes will be the same whether for a single battery or for a number of similar sized batteries in series, and should be as stated on one of the instructions labels attached to the batteries. DURATION OF CHARGE.—The charge must be continued for a total of 30 hours, which, if more convenient, can be divided into two periods of fifteen hours each. No current should be taken from the battery until it has received this full 30 hours charge. TEMPERATURE DURING CHARGE.—During the charge the temperature of the battery should be occasionally ascertained by means of a suitable thermometer, and if it reaches 100° Fahr. the current should be reduced and the duration of the charge increased proportionately. As temperature rates are not easily taken, on account of the only access to the acid being through the vents of the cells, a special thermometer should be obtained suitable for inserting through the vent into, the acid on top of the plates (see Diagram 5). VOLTAGE ON COMPLETION OF CHARGE.—When the battery has received its full charge, it should give a total voltage equivalent to 2.4 volts per cell, i.e., a 6 volt battery should register 7.2 volts, and a 12 volt battery should register 14.4 volts directly it is disconnected from the charging circuit. ACID LEVEL AND SPECIFIC GRAVITY.—At the end of the charge the acid level should be inspected, and if it has become low it should be levelled up while the plates are gassing by adding pure distilled water only, unless any of the acid has been spilt, in which case a little dilute acid may be added to bring the specific gravity to the correct figure. On the completion of the charge this should be about 1.280 at a temperature of 60° Fahr. after levelling up the acid. The vents plugs or caps should be replaced, and any acid that may have got out in the form of spray on to the tops of the cells should be carefully wiped off. Diagram 5. ACID LEVEL ½ IN. ABOVE TOPS OF PLATES | ||