  Introduction.—The practical development of the storage battery is comparatively recent, although a knowledge of the phenomena upon which its actions are based, dates back to 1801. In 1800, the year made memorable by Volta's discovery of the galvanic battery, Nicholson and Carlisle found that a current from Volta's cell could decompose water.
Fig. 1,046.—One plate or "grid" of a type of storage cell constructed by inserting buttons or ribbons of the proper chemical substances in perforations. Some such cells use crimped ribbons of metallic lead for inserting in the perforations, others pure red lead or other suitable material.
Figs. 1,047 to 1,050.—Electric Storage Battery Co. plates. Fig. 1,047, "Manchester" positive plate; fig. 1,048, box negative plate; fig. 1,049, "Tudor" positive plate; fig 1,050, pasted negative plate. Ques. To what use is the storage battery sometimes put in electric lighting or power stations? Ans. To carry the "peak" of the load; that excessive portion of the load which, for instance, in electric lighting stations Fig. 1,051.—"Unformed" plate of one pattern of Gould storage cell. The particular plate shown has total outside dimensions of 6×6 inches. The clear outline of the grooves indicates absence of oxides, due to action of "forming" solutions, or charging current. Theory of the Storage Battery.—The action of the storage battery is practically the same as that of the primary battery and it is subject to the same general laws. The cells of a storage battery are connected in the same way as primary cells, and when charged is capable of generating a current of electricity in a manner similar to that of a primary battery. It differs, however, from the primary battery in that it is capable of being recharged after exhaustion by passing an electric current through it in a Figs. 1,052 and 1,053.—Electric Storage Battery Co., type H "exide" plates. This form of plate is used for large "stand by" batteries. Fig. 1,052, positive plate; fig. 1,053, negative plate. Ques. Describe a storage cell. Ans. A storage cell consists of plates or of grids in an electrolyte, of such a character that the electrical energy supplied to it is converted into chemical energy (a process called charging). The chemical energy can be reconverted into electrical energy (a process called discharging). Ques. Describe the electrolyte generally used. Ans. It consists of a weak solution of sulphuric acid which permits ready conduction of the current from the primary battery, the greater the proportion of acid within certain limits, the smaller the resistance offered. Fig. 1,054.—Elements of 6 volt 40 ampere hour "Aplco" portable (3 cell) storage battery. The grids are made from an alloy of lead and antimony; hard lead straps which are burned together, are used for joining the plates. Specially treated separators are used. Ques. What is the effect of the current passing through the electrolyte? Ans. It decomposes the water into oxygen and hydrogen; this is indicated by the formation of bubbles upon the exposed surfaces of both plates, these bubbles being formed by oxygen
Ques. What is the prime condition for operation of a storage battery? Ans. The resistance of the electrolyte should be as low as possible in order that the current may pass freely and with full effect between the electrodes. If the resistance of the electrolyte be too small, the intensity of the current will cause the water to boil rather than to occasion the electrolytic effects noted above. Ques. What happens when the charging current is discontinued, and the two electrodes joined by an outside wire? Ans. A small current will flow through the outside circuit, being due to the recomposition of the acid and water solution. The process is in a very definite sense a reversal of that by which the current is generated in a primary cell.
Types of Storage Battery.—There are three classes of storage cell which are commercially important: 1. Plante cells; According to construction secondary cells may be classified as follows: 1. Lead sulphuric acid cells;
Ques. Describe the Plante type. Ans. In the Plante type the lead is chemically attacked and finally converted into lead peroxide, probably after it has gone through several intermediate changes. The plates are all formed as positive plates first and then all that are intended for negative plates are reversed, the peroxide being changed into sponge lead. Figs. 1,055 and 1,056.—Willard plates; fig. 1,055, negative plates; fig. 1,056, positive plates. Both positive and negative plates are of the PlantÉ type, made from one integral piece of rolled lead. These are grooved plates. The projections are tapered, that is, they are wider at the base than at the surface, for strength. The center web of each positive plate is tapered from the top of the plate downward to secure uniform distribution of the current all over the surface of the plate. Fig. 1,057.—Wood separator for spacing the plates, as used in the Willard storage cells. Fig. 1,058.—Positive plate. Fig. 1,059.—Perforated rubber separator. Fig. 1,060.—Wood separator. Fig. 1,061.—Negative plate. Fig. 1,062.—Hard rubber cover. Fig. 1,063.—Vent plug. Fig. 1,064.—Pillar connecting strap. Fig. 1,065.—Hard rubber jar. Fig. 1,066.—Complete element. Figs. 1,058 to 1,066.—Parts of the Willard "Autex" automobile cells. Ques. What is done to make the Plante plate more efficient? Ans. The surfaces are finely subdivided, the following methods being those common: scoring, grooving, casting, laminating, pressing, and by the use of lead wool. Ques. Describe the Faure or pasted type. Ans. This form of plate is constructed by attaching the active material by some mechanical means to a grid proper. The active material first used for this purpose was red lead, which was reduced in a short time to lead peroxide when connected as the positive or anode, or to spongy metallic lead when connected as the cathode or negative, thus forming plates of the same chemical compound as in the Plante type.
Ques. How do Faure plates compare with those of the Plante type? Ans. They are usually lighter and have a higher capacity, but have a tendency to shed the material from the grid, thus making the battery useless.
The Electrolyte.—Sulphuric acid is generally used as electrolyte; the acid should be made from sulphur and not from pyrites, as the latter is liable to contain injurious substances. Ques. How is the electrolyte prepared? Ans. One part of chemically pure concentrated sulphuric acid is mixed with several parts of water. The proportion of water differs with several types of cell from three to eight parts, as specified in the directions accompanying the cells. Figs. 1,067 to 1,079.—Willard connecting straps and connectors. Ques. What test is necessary in preparing the electrolyte? Ans. In mixing the water and acid, the hydrometer should be used to test the specific gravity6 of both the acid and the solution. The most suitable acid should show a specific gravity of about 1.760 or 66° BaumÉ. Ques. In preparing the electrolyte, how should the water and acid be mixed? Ans. The mixture should be made by pouring the acid slowly into the water, never the reverse. As cannot be too strongly stated, in mixing, the liquid should be stirred with a clean wooden stick, the acid being added to the water slowly; the latter is corrosive and will painfully burn the flesh.
Ques. What is the effect of mixing the acid and the water? Ans. The mixture becomes hot. Before using, the mixture should be allowed to cool. Ques. What kind of a vessel should be used? Ans. The vessel should be of glass, glazed earthenware, or lead. Ques. At what density is the resistance of dilute sulfuric acid at a minimum? Ans. At 1.260.
Ques. What is the effect of a deep containing vessel? Ans. Parts of the plate surface may do more than their share of the work due to the difference in the density of the electrolyte at the top and bottom. The containing vessel should, therefore, Ques. What is the effect of changes in temperature on the electrolyte? Ans. The resistance of the electrolyte is changed, being less for increase of temperature. Figs. 1,080 to 1,084—Acid hydrometers for liquids heavier than water. Fig. 1,080, standard storage battery hydrometer with guiding points designed for "hydrometer syringe," shot bulb, with red line at 25 BaumÉ, 5 inches long, double scale 10 to 40 BaumÉ, 1.050 to 1.400 specific gravity. Fig. 1,081, plain hydrometer with shot bulb, 5 inches long, double scale 10 to 40 BaumÉ, 1.050 to 1.400 specific gravity. Figs. 1,082 and 1,083, hydrometer with small flat bulb, used in car lighting batteries, shot bulb, 4½ inches long, single scale, reading from 1.100 to 1.250 specific gravity. Fig. 1,084 jar for hydrometers. Ques. How should the cells be filled? Ans. Enough of the electrolyte should be poured into the jars to completely cover the plates, or to within about a half Ques. What change takes place after filling the jars? Ans. The specific gravity of the electrolyte will fall considerably, but will rise again when the battery is charged. Ques. What may be said with respect to the density of the electrolyte? Ans. It should never exceed 1.200 when the battery is fully charged. Ques. How much electrolyte is used per 100 ampere hours battery capacity, on an 8 hour rating? Ans. About ten pounds; in automobile batteries, about four pounds is sufficient. Fig. 1,085.—The hydrometer syringe; a convenient device for testing electric vehicle cells. By slightly compressing the bulb and inserting the slender tube through the vent hole in the cover of the cell sufficient acid may be drawn up to float the hydrometer within the large glass tube, and the reading can be made at once. The acid is returned to the cell by again compressing the bulb, and the reading of the next cell taken. The laborious and uncleanly method of drawing out sufficient acid by a syringe is thus avoided. Ques. What may be said with respect to impurities in the electrolyte? Ans. The electrolyte should be free from chlorine, nitrates, acetates, iron, copper, arsenic, mercury, and the slightest trace of platinum.
Figs. 1,086 to 1,089.—The "Champion" Accumulator; views showing parts and assembly. Fig. 1,086, empty plate; fig. 1,087, filled plate; fig. 1,088, complete element, small type; fig 1,089, cell assembled. The plates are of the envelope type and are made thick. The active material is held firmly in place by a covering of lead. A few thick plates are used instead of many thin ones. The following tests should be made for impurities before the electrolyte is poured in the cells:
Fig. 1,090.—One cell of the Gould storage battery for electric vehicle use. According to the data given by the manufacturers, this cell, containing four negative and three positive plates, has a normal charging rate of 27 amperes; a distance rate of 22 amperes for four hours; a capacity of 81 ampere hours at 3 hours discharge, and of 90 ampere hours at 4 hours discharge. Forty such cells are generally used for an average light vehicle battery.
Ques. What should be done with old electrolyte? Ans. When a battery is taken down the electrolyte may be saved and used when re-assembling the battery, providing great care be exercised when pouring it out of the jar, so as not to draw off with it any of the sediment. It should be stored in convenient receptacles, preferably carboys, which have been thoroughly washed and never used for any other purpose. Fig. 1,091.—Phantom view of an "Exide" sparking or ignition battery. It contains three cells. In this type, the terminal lug has been designed to obviate the creeping of the electrolyte with its accompanying corrosion. The positive and negative terminals are for identification.
Voltage of a Secondary Cell.—This depends on the density of the electrolyte, the character of the electrodes and condition of the cell; it is independent of the size of the cell. The voltage of a lead sulphuric acid cell when being charged is from 2 to 2.5 volts. While the cell is being discharged, it decreases from 2 to 1.7 volts. The voltage due to the density of the electrolyte may be calculated from the following formula: V = 1.85 + .917 (S - s) in which V = voltage; Fig. 1,092.—The Exide storage cell. The positive and negative plates are separated by thin sheets of perforated hard rubber, placed on both sides of each positive plate. The electrolyte and plates are contained in a hard rubber jar. Fig. 1,093.—An Exide battery of five cells. The box which holds the cells is usually made of oak, properly reinforced, with the wood treated to render it acid proof. The terminals as shown, consist of metal castings attached to the side of the box and plainly marked. Connection for Charging.—The dynamo cable connections may be made either before or after filling the cells. In making these connections great care should be taken to be sure that the positive terminal of the battery is connected to the positive lead of the dynamo, and that the negative terminal of the battery Figs. 1,094 to 1,109.—Parts of the "Exide" sparking battery. A, positive plate; B, negative plate; C, wood separator; D, positive strap; E, negative strap; F, terminal lug; H, connector; I, terminal bolt connector, stud, thumb nut and hexagonal nut; J, copper washer for bolt connector; L, hard rubber jar; M, hard rubber cover; N, hard rubber cylinder vent; O, vent plug for cylinder vent; R, wood case; S, strap handle; T, fitting for strap handle. The "Exide" sparking battery is also adapted for electric lighting of automobiles, for head lights, tail lights, side and interior lights. The polarity of the dynamo wires being determined, they may be joined to the proper terminals by means of suitable clamps or by solder. Wherever possible the dynamo should be of the direct current, shunt wound, or special compound type, but in cases where only alternating current can be obtained, suitable rectifiers or converters should be used for changing it to direct current. Charging.—Before beginning to charge a storage battery, it should be gone over carefully, and any cell that is not up to the standard should be disconnected and put in working order before being replaced. In general, if the current used in charging be too large, it will waste energy by evolving an excess of heat and gas; if too small, an insulating deposit of white lead sulphate will be formed on the positive plate, thereby preventing the formation of the proper amount of lead peroxide. Figs. 1,110 and 1,111.—Switchboard and motor dynamo circuit connections for charging a battery from direct current mains. Ques. How should a battery be charged for the first time? Ans. It is essential that the current be allowed to enter at the positive pole at about one-half the usual charging rate prescribed, but after making sure that all necessary conditions have been fulfilled, it is possible to raise the rate to that prescribed by the manufacturers of the battery. Ques. What is the usual period for charging a new battery? Ans. With several of the best known makes of storage battery the prescribed period for the first charge varies between twenty and thirty hours. Figs. 1,112 and 1,113.—Switchboard and motor generator circuit connections for charging a battery from alternating current mains. The connections of a third wire are shown, for use in case a three phase circuit is available. Ques. How is the electrolyte affected by the first charge? Ans. A change of specific gravity occurs. The specific gravity should be about 1.200 when the solution is poured into the cells.
Fig. 1,114.—Plates of Edison storage battery. The positive or nickel plate consists of one or more perforated steel tubes, heavily nickel plated, filled with alternate layers of nickel hydroxide and pure metallic nickel in excessively thin flakes. The tube is drawn from a perforated ribbon of steel, nickel plated, and reinforced with eight steel bands, equidistant apart, which prevent the tube expanding away from and breaking contact with its contents. The tubes are flanged at both ends and held in perfect contact with a steel supporting frame or grid made of cold rolled steel, nickel plated. The negative or iron plate consists of a grid of cold rolled steel, nickel plated, holding a number of rectangular pockets filled with powdered iron oxide. These pockets are made up of very finely perforated steel, nickel plated. After the pockets are filled they are inserted in the grid and subjected to great pressure between dies which corrugate the surface of pockets and force them into good contact with the grid. Ques. What strength of current should be used in charging a cell? Ans. It should be in proportion to the ampere hour capacity of the cell.
Ques. What should be the voltage of the charging current before closing the charging circuit? Ans. The voltage should be at least ten per cent. higher than the normal voltage of the battery when charged. Fig. 1,115.—Complete element of Edison storage battery with insulators. After the plates are assembled into a complete element, narrow strips of treated hard rubber are inserted between the plates, thereby separating and insulating them from each other. The side insulator is provided with grooves that take the edges of the plates, thereby performing the dual function of separating the plates and insulating the complete elements from the steel container. At the ends of the element, that is between the outside negative plates and container, are inserted smooth sheets of hard rubber. At the bottom, the element rests upon a hard rubber rack or bridge, insulating the plates from the bottom of container. Fig. 1,116.—Four Edison cells (type A-4) in wooden tray. Ques. What indicates the completion of a charge? Ans. When a cell is fully charged the electrolyte apparently boils and gives off gas freely. The completion of a charge may Ques. How should the voltage be regulated during the first charge? Ans. It should be allowed to rise somewhat above the point of normal pressure.
Fig. 1,117.—Cell of Edison storage battery. The jar or container is of nickel plated sheet steel with welded seams; the walls are corrugated to give strength. The cell cover, of sheet steel, has four mountings, two being pockets to contain stuffing boxes about the terminal posts. One of the other two is a separator which separates spray from the escaping gas while the battery is charging. The fourth mounting is for filling with electrolyte. The electrolyte consists of a 21% solution of potash in distilled water with a small per cent. of lithia. The density of the electrolyte does not change on charge or discharge. Ques. How often should a battery be charged? Ans. At least once in two weeks, even if the use be only slight in proportion to the output capacity.
Fig. 1,118.—Diagram illustrating method of charging storage battery of stationary gas engine ignition system; the system is simple to install and will give satisfactory results. Two storage batteries are used, one being charged while the other is operating the sparking coil. Where charging current is available at the point where the batteries are used, the following diagram shows the system of connections, which can be easily followed, A represents the source of charging current and B the bank of lamps (or other resistance, such as an ordinary rheostat) sufficient to cut down the charging voltage to that required by the battery. C and D are two double pole double throw knife switches connected at their hinges to two batteries, E and F, each consisting of a group of cells. G represents the leads to the sparking coil terminals. From the diagram, it will readily be seen that by throwing the switches in opposite directions one battery will be charging while the other battery is discharging to the engine, thus giving a constant source of supply, and insuring that the spare battery will be full and ready for service by the time the other is discharged. The method of determining the necessary resistance for cutting down the line voltage for charging the battery is illustrated by the following example: If a battery require about 3 amperes for charging, how is this current obtained from a 110 volt circuit? Each 16 candle power carbon filament lamp in the lamp bank would give approximately 1/3 ampere with the cells in series in the lamp circuit. Therefore, 3 x 3 or 9 lamps should be used in parallel to give 3 amperes. Ques. If in charging a battery, one or more of the cells do not boil at the completion of the charge, or fail to show the proper voltage, what should be done? Ans. The charging must be continued until the cadmium test shows the required voltage, but if the prolonging of the charge be liable to damage the plates in the other cells, the defective cell or cells should be cut out of circuit when the battery discharges and then placed in circuit again when the battery is Figs. 1,119 and 1,120.—Emergency connections for weak ignition battery. It sometimes occurs through carelessness or neglect, that the storage battery is discharged so low that the engine explosion will not take place, and it is necessary to run somehow or other for a short time. In such cases the following suggestion may be followed: If there be two storage batteries, connect them in series. If there be one storage battery and a set of dry cells, connect the positive terminal of the storage battery to the negative or outside terminal of the dry cell; set and connect to the coil leads as if they were one battery. The above suggestions should only be followed in emergency, for it may injure the coils, and is harmful to the battery. Ques. How is the cadmium test made? Ans. A plate of cadmium is mounted in a hard rubber frame and immersed in the electrolyte. The test consists in taking voltage readings between the cadmium plate and the positive or negative plates of the cell. During charge the cadmium plate reads negative to the negative plate, until the cell is about full, Ques. Name some portable instruments that should be provided for testing batteries. Ans. 1, a hydrometer syringe (specific gravity tester); 2, an acid testing set (can be used instead of the syringe); 3, a low reading voltmeter; 4, suitable prods, and 5, a thermometer. Ques. What precaution should be taken in charging a battery? Ans. Care should be taken not to have a naked flame anywhere in its vicinity.
Ques. What is the effect of varying the charging current? Ans. In charging a storage cell, particularly for the first time, a weaker current than that specified may be used with the same result, provided the prescribed duration of the charge be proportionally lengthened. The battery may also be occasionally charged beyond the prescribed voltage, ten or twenty per cent. overcharge effecting no injury, although if frequently repeated, it shortens the life of the battery. Ques. What are the charge indications? Ans. The state of the charge is not only indicated by the density of the electrolyte and the voltage of the cell, but also by the color of the plates, which is considered by many authorities as one of the best tests for ascertaining the condition of a battery. Figs. 1,121 and 1,122.—Two methods of charging from a direct current lighting system. The simplest method of charging is from an incandescent light circuit, using lamps connected in parallel to reduce the voltage to that of the battery, the current being adjusted by varying the number of lamps in circuit. The group of lamps is in series with the battery to be charged, and the combination is connected across the circuit furnishing the current. If the charging source be a 110-120 volt circuit, and the rate required be 6 amperes, twelve 16 c. p. or six 32 c. p. lamps, in parallel, and the group in series with the battery, will give the desired charging rate, unless high efficiency lamps be used, when more will be required. In case a lower charging rate, say 2 amperes be used, then a proportionately fewer number of lamps will be needed; but the length of time required to complete the charge will be correspondingly increased. Instead of lamps, as in fig. 1,121, a rheostat is sometimes used, as shown in fig 1,122. Its resistance should be such as to produce, when carrying the normal charging current, a drop in volts equal to the difference between the pressure of the charging source and that of the battery to be charged; thus, if a battery of three cells, giving 6 volts, is to be charged from a 110 volt circuit at a 6 ampere rate, the resistance would be, according to Ohm's law, Ques. What are the colors of the plates? Ans. In the case of formed plates, and before the first charging, the positives are of a dark brown color with whitish or reddish gray spots, and the negatives are of a yellowish gray. The whitish or reddish gray spots on the positive plates are small particles of lead sulphate which have not been reduced to lead peroxide during the process of forming, and represent imperfect sulphation.
Ques. How are the best results obtained in charging? Ans. The rate of charge should be normal, except in cases of emergency. At such a rate, unless the constant voltage method be employed, the cell may be considered full when the voltmeter reads 2.5 volts during charge. The electrolyte should be kept at uniform density throughout the cell; when water is added, because of evaporation, it should be added by means of a funnel reaching to the bottom of the cell. Care should be taken never to add acid after evaporation; otherwise the electrolyte will be too heavy. Hydrometer readings should be taken regularly; Ques. What voltage should be used in charging? Ans. At the beginning of the charge the voltage should be about 5 per cent. higher than the normal voltage of the battery, unless the latter has been overdischarged, in which case the difference of pressure should not exceed 2 per cent., otherwise the current might be too large. Fig. 1,123.—Diagram showing charging connections for "Exide" duplex sparking battery. C, charging source; D, double pole single throw switch; E, single pole single throw switch; M, lamp resistance "main" battery; R, lamp resistance "reserve" battery. Ques. In what two ways may batteries be charged? Ans. They may be charged either at constant current or at constant voltage.
Ques. How may the charging current be kept constant? Ans. Its voltage should be gradually increased, first to about 10 or 15 per cent. above the voltage of the battery, and kept at that point nearly to the end of the charge, where in consequence of the rapid rise of pressure in the battery it might become necessary to increase the voltage of the current to 30 or 40 per cent. above the normal of the battery. Figs. 1,124 to 1,126.—Electric Storage Battery Co. chloride cells. The voltage of cells of all capacities is slightly above 2 volts on open circuit, and during discharge at the 8 hour rate it varies from that point at the beginning to 1.75 volts at the end. Ques. What tests should be made while charging? Ans. Occasional voltage and cadmium readings of each cell should be taken for the purpose of ascertaining their condition and the behavior of the separate plates. Ques. What tests should be made after charging? Ans. Each cell should be tested with a low reading voltmeter and hydrometer about once a week. If any cell read low, it should be cut out and examined to see if any material has been Charge Indications.—The state of the charge is not only indicated by the density of the electrolyte and the voltage of the cell, but also by the color of the plates, which is considered by many authorities as one of the best tests for ascertaining the condition of a battery.
The formation of these scales during charging indicates that the maximum charging current is too large and should be reduced until the scales or white deposits fall off or disappear, after which the current can be increased again. Ques. Describe the behavior of the electrolyte during discharge. Ans. There is a definite change in the density of the electrolyte for a given amount of discharge.
Fig. 1,127.—Electric Storage Battery Co., arc lead burning outfit. In assembling a storage battery element, a negative plate is laid down with a separator on it, then a positive plate, separator, negative plate, etc. The plates are so placed that all the lugs of the positive plates are on one side and all the lugs of the negative plates are on the other side. A strip, consisting of flat strips of lead or lead alloy, having rectangular openings in it of the same dimensions as the cross section of the lug of the plates, these openings being spaced to register with the lugs, is then placed over the plate lugs of the positive plates and a similar strap is placed over the lugs of the negative plates. The lugs are then burned into integral union with the straps. Ques. Define the term "boiling." Ans. Boiling means the rapid evolution of gas when a cell is nearly charged. Ques. What causes boiling? Ans. The amount of sulphate to be converted into peroxide becomes less and less as the charge progresses and the plates therefore become virtually smaller, so that the current becomes too large for the work demanded of it. The result is, that part of the current not actually used in the formation of peroxide decomposes the electrolyte into its constituent elements. Ques. Why do the gases evolved produce a less milky appearance of the electrolyte when a battery has been in use for a considerable time? Ans. The plates are better formed; consequently a larger charging current can be used without producing "boiling". Fig. 1,128.—Hydrogen gas generator for lead burning. A complete lead burning outfit consists of the following parts: 1, hydrogen gas generator; 2, trap for cleaning the gas and for preventing the flame getting back in the generator; 3, air pump; 4, air tank; 5, blow pipe; 6, lead burner's mixing tee; 7, length of 150 feet 5/16 inch soft rubber tubing. When the generator is to be used for lead burning, connect up the different parts of the apparatus as shown. Fill the trap 2/3 full with water and be sure to connect the gas generator to the nipple on the bottle marked B. The stop cocks N and C must be closed. See that the rubber plug at D is secured in place. Put the required amount of zinc in the opening at H. (No. 1 generator requires: 15 lbs. zinc, 9 gals, water, 3 gal. vitriol. No. 2 generator requires: 20 lbs. zinc, 15 gals. water, 5 gals. vitriol). After putting in the zinc, add the water and then the sulphuric acid, and note that the water must always be put in before the acid. When making the connection be sure that there are no low points in the hose between E and N, as water is liable to accumulate at these low places, which will make the gas damp which is detrimental to the burning. If water get into the line, kink the hose between F and B, detach the hose at E and blow out the water with air by opening the cocks, N, C and V. The length of the hose between T and X must not be longer than five feet as the cocks N and C must always be within the reach of the man who is using the flame. When ready to use the flame, open N which allows the hydrogen gas to escape. Light the same with a match and adjust the air cock C until the desired flame is obtained. Different classes of work require different flames, which can be obtained by changing the tips and by varying the amount of gas and air with the cocks N and C. When the generator is laid up for the night, or when the charge is exhausted, pull the hose off at F and draw off the solution by removing the plug at D. The generator should then be thoroughly washed by pouring water in A. Ques. What may be said of charging a battery as quickly as possible? Ans. As a general rule, such a procedure should not be adopted unless the battery be thoroughly discharged. Ques. What precaution should be taken? Ans. The danger to be avoided in rapidly charging a cell is its tendency to heat. Ques. What apparatus is necessary in charging a battery? Ans. The battery may be charged from direct current mains having the proper voltage. A current as near uniform as possible is required, and existing conditions must be met in each separate case. Sometimes a motor dynamo set with a regulating switchboard is used. Such an apparatus consists of a direct current dynamo, driven direct from the shaft of a motor, which, in turn, is energized by current from the line circuit.
Charging Through the Night.—If an electric vehicle, after a late evening run, is to be used in the morning, the battery may be charged during the night without an attendant being present; but in doing this great care must be taken not to excessively overcharge. A careful estimate of the amount of current required should be made and the rate of charge based on this estimate.
Ques. What precautions should be taken in charging a battery out of a vehicle? Fig. 1,129.—Interior view Northwestern storage battery. The positive plate is of double grid construction, and the negative plate consists of a special staggered grid. The separators used between the plates are hard rubber, ribbed on one side so as to prevent the positive plate from buckling. It is perforated so as to allow a free circulation of the electrolyte and to decrease the internal resistance. Rubber separators are better than the commonly used wood or paper separators because they prevent local action. The flat side of each separator is placed against a positive plate, preventing shedding or jolting of the active material of the plate. This checks deterioration. The jars are made of rubber composition; the walls are thick and the covers well fitted to avoid spilling the electrolyte. All Northwestern batteries are contained in rubber composition jars. The walls are thick and the covers fit tightly to prevent spilling the acid. A hard wood box, treated with a moisture repellant is used for the outer case. These batteries are made in any voltage desired, the ampere capacity ranging from 25 amp. hrs. to 300 amp. hrs. Ans. When a battery is being overhauled, the cells must be connected together in series and to the charging source in Charging Small Cells.—For cells of the portable type, having capacities from 10 to 100 ampere hours, the normal charging and discharging rate should be about one-tenth the stated capacity, but the discharging rate may be increased to double this value, in case of necessity. If the cells be provided with formed plates and not charged, the jars should be filled with the proper electrolyte, and then charged for at least 10 hours steady, or until they boil, then they may be discharged. In the case of unformed plates, the charging should be from 30 to 40 hours, until the cells boil, and the plates assume their proper color. Ques. How are small cells easily charged from 110 or 220 volt circuits? Ans. This may be conveniently done by inserting in one of the charging leads an incandescent lamp which will pass the required quantity of current. If the current required be as large as 10 amperes, a suitable resistance or 10 lamps in parallel, each passing one ampere, may be used. Great care should be taken to see that the battery is connected properly. Period of Charging a New Battery.—In the case of batteries provided with formed plates, the first charge should extend over a period of not less than 30 consecutive hours, without stopping, if possible, or for periods of not less than 10 hours a day for three consecutive days. The electrolyte will then commence to "boil" or "gas," assuming a milky appearance due to the ascending bubbles of gas. At this stage the density of the electrolyte as shown by the hydrometer placed in each cell should be at least 1.200; it is essential that the charging should be continued until every cell boils equally. From this point the charging should be prolonged until the pressure, as determined by a voltmeter or a cadmium tester, rises to about 2.55 volts. Fig. 1,130.—The Willard underslung battery box for automobiles. The general tendency in automobile design, is to keep everything off the running board as far as possible, and to get tool boxes, battery boxes, etc., placed somewhere under cover. To meet these conditions the box here illustrated is arranged so that it can be underslung beneath the rear footboard or supported on auxiliary cross members made of strap iron and attached to the side members of the chassis. It is usually suspended under the rear footboard or the rear seat. The box has a chemically treated wood lining to make it acid proof. The lining is so made that there is air space between the battery and the sides of the box, except at the corners. Ventilation is thus obtained and the battery kept dry. Accumulation of water or spilled electrolyte in the bottom of the box is prevented by grooves in the bottom board, extending downward from the corners to an outlet at the center of the board. The box is also fitted with rubber bushings in the holes where wire leaves the battery box.
In regular charging, the rate should be rapid when the battery is nearly exhausted, but it should be greatly reduced at the end of the charge after passing the point of boiling. Charging at too low a rate is always injurious. Ques. What may be said with respect to the capacity of a new battery? Ans. A new battery will never give its full capacity till after about twenty discharges. During this time it should be given about 25% overcharge. After that, 10% overcharge, that is, 10% more charge than was taken out, will be sufficient for ordinary work. High Charging Rates.—Occasionally it is desirable to charge a battery as quickly as possible. As a general rule, such a procedure should not be adopted unless the battery be thoroughly discharged, and not then, unless done by a person who thoroughly understands what he is about; battery makers will always furnish data and directions to meet emergencies.
Fig. 1,131.—Instructions for taking voltage readings ("National" batteries). The batteries are made up of several cells, usually two or three, each cell representing approximately 2 volts when battery is on "open circuit" (neither charging nor discharging). It is sometimes advisable to take individual readings of the cells, both to determine on charge if all the cells be evenly charged, and also on discharge to be sure that the cells are evenly discharged. To do this, a low-reading voltmeter must be used with prods attached to the voltmeter leads that can be forced into the terminals so as to insure good contacts. To test the positive end cell, put the positive prod on the positive terminal of the battery and the negative prod into small hole back of positive terminal in hard rubber cover. Middle cell (in 6 volt, type "Y" batteries) is tested by inserting the positive prod in the small hole back of the positive terminal, and the negative prod in small hole back of negative terminal. In the 120 ampere hour, Auto type of battery, the middle cell is tested by inserting the positive prod in the small hole back of the positive terminal and the negative prod on the middle terminal. The negative end cell is tested by putting the negative prod on the negative terminal and the positive in the small hole in rubber cover back of the negative terminal. A charging cell at end of charge should read about 2.55 volts. A fully charged cell on open circuit should read about 2.1 volts. Since open circuit readings vary under different conditions, as to age, acid, etc., little significance should be attached to them. A discharged cell voltage will vary considerably with the many different coils, engines, etc., but in the majority of cases should read between 1.8 to 1.9 volts, while motor is in operation. For rapid charging, when a battery has to be charged in four hours, the current should vary about as follows:
Mercury Arc Rectifier.—This is a device for obtaining direct current from alternating current for use in charging storage batteries. The transformation is obtained at a low cost, because the regulation is obtained from the alternating side of the rectifier, while the current comes from the direct current side. Figs. 1,132 to 1,134.—Mercury arc rectifier outfit, or charging set. The cuts show front, rear, and side views of the rectifier, illustrating the arrangement on a panel, of the rectifier tube with its connection and operating devices. The theory is as follows: In an exhaust tube having one or more mercury electrodes, ionized vapor is supplied by the negative electrode or cathode, when the latter is in a state of "excitation." This condition of excitation can be kept up only as long as there is current flowing toward the negative electrode. If the direction of the voltage be reversed, so that the formerly negative electrode is now positive, the current ceases to flow, since in order to flow in the opposite direction it would require the formation of a new negative electrode, which can be accomplished only by special means. Therefore, the current is always flowing toward one electrode—the cathode, which is kept excited by the current itself. Such a tube would cease to operate on Fig. 1,135.—Elementary diagram of mercury arc rectifier connections. A, A´, graphite anodes; B, mercury cathode; C, small starting electrode; D, battery connection; E, and F reactance coils; G and H, transformer terminals; J, battery. Ques. Describe the construction and operation of a mercury arc rectifier. Ans. Fig. 1,135 is an elementary diagram of connections. The rectifier tube in an exhausted glass vessel in which are two graphite anodes A, A´, and one mercury cathode B. The small starting electrode C is connected to one side of the alternating circuit, through resistance; and by rocking the tube a slight arc is formed, which starts the operation of the rectifier tube. At Ques. How is a mercury arc rectifier started? Ans. A rectifier outfit with its starting devices, etc., is shown in figs. 1,132 to 1,134. To start the rectifier, close in order named line switch and circuit breaker; hold the starting switch in opposite position from normal; rock the tube gently by rectifier shaker. When the tube starts, as shown by greenish blue light, release starting switch and see that it goes back to normal position. Adjust the charging current by means of fine regulation switch on the left; or, if not sufficient, by one button of coarse regulation switch on the right. The regulating switch may have to be adjusted occasionally during charge, if it be desired to maintain the charging current approximately constant. Capacity.—The unit of capacity of a storage cell is the ampere hour, that is, the ability to discharge one ampere continuously for one hour. For instance, a 100 ampere hour battery will give a continuous discharge of 12½ amperes for eight hours. It should theoretically give a discharge of 25 amperes continuously for four hours, or 50 amperes for two hours, but in reality, the ampere hour capacity decreases with an increase of discharge rate. It requires, theoretically .135 ounces of metallic lead on either element reduced to sponge lead or to lead peroxide to produce one ampere hour; in practice, from four to six times this amount is required.
Experiments show that from .5 to .8 ounces of sponge lead, and from .53 to .86 ounces of metallic lead converted into peroxide, are required on their respective elements to produce a discharge of one ampere hour at ordinary commercial rates. The capacity increases with the temperature, being about one per cent. for each degree Fahr. increase in temperature. Battery capacity depends on the size and number of plates; the quantity of active material present, and the quantity of electrolyte. For an eight hour rate of discharge and 60 degrees temperature, the capacity of American batteries varies from 40 to 60 ampere hours per square foot of positive plate surface ( = 2 × number of positive plates in parallel × length × breadth). The following table gives the variation of capacity for different rates of discharge:
Fig. 1,136.—"Exide" connector puller for removing connectors. Ques. How may the capacity of a battery be increased? Ans. By mixing organic materials with the lead oxide, but any such mixture is always accompanied by a rapid deterioration of the plates. Discharging.—In discharging a battery its voltage should never be allowed to fall below 1.8 volts, under load, thus leaving about 30 per cent. of the total capacity unused. The normal discharging current may be equal to the normal charging current, but a discharge equal to 3 or 4 times the normal may be given Figs. 1,137 to 1,151.—Parts of the Witherbee battery. 1, jar; 2, inside cover; 3, cover; 4, handle; 5, vent cap; 6, cover, screws, nuts and washers; 7, handle eyes, nuts and washers; 8, rubber covered nut; 9, spannernut; 10, plate strap for positive plates; 11, plate strap for negative plates; 12, rubber separator; 13, wood separator; 14, positive group of plates; 15, negative group of plates; 16, positive plate; 17, negative plate; 18, cell connector. An element consists of a complete set of plates bound together on strap, with wood and rubber separators for a single cell. Positive plates are brown, negative plates, gray. Ques. What is the effect of discharging too rapidly? Ans. It tends to break the plates, and in the case of pasted plates, a very sudden discharge will dislodge the paste. Ques. How is the discharge capacity of a storage battery stated? Ans. In ampere hours. This, unless otherwise specified, refers to its output of current at the eight hour rate. Most manufacturers of automobile batteries specify only the amperage of the discharge at three and four hours. Thus, at the eight hour rate, a cell which will discharge at ten amperes for eight hours is said to have a capacity of eighty ampere hours. It does not follow that eighty amperes would be secured if the cell were discharged in one hour. It is safe to say that not more than forty amperes would be the result with this rapid discharge.
Ques. What should be the maximum rate of discharge? Ans. The one-hour rate; this when used, should not extend over fifteen or twenty minutes. In the case of regulating batteries a forty-five minute rate of discharge may be allowed for one or two minutes during great fluctuations of load. Ques. How does the capacity decrease? Ans. It decreases with the increase in current output.
Fig. 1,152.—The Edison alternating current rectifier. It consists of an electro-mechanically operated valve which allows current waves of only one polarity to pass through it from the alternating current circuit to the battery which is to be charged. An indicating snap switch of the usual form controls the starting and stopping of the charging current. The rectifier gives any desired charging rate within its capacity. The illustration shows the rectifier connected up and charging an ignition battery of five Edison cells. The connections consist of the usual connecting cord and plug and a charging lead running from the plus side of the charging terminals on the rectifier to the plus pole of the battery, and another lead connecting the negative terminals as shown. In turning the snap switch to the "on" position, the proper charging current will flow into the battery. When charging is completed, the switch is turned to the "off" position and the battery leads disconnected. Ques. What, in general, are the indications of the quantity of electricity remaining within a cell? Ans. The voltage, and the density of the electrolyte. Ques. What should be done after discharging? Ans. Whenever possible the battery should be immediately charged. The Battery Room.—Precautions should be taken to prevent any direct sunlight falling on the battery cells in glass jars, as the breakage of such jars due to unequal expansion of the different portions of the glass, is a source of constant trouble and danger. Fig. 1,153.—Permanent connections for Edison rectifier. As shown, the rectifier is connected to a small switch and cutout. The exclusion of direct sunlight also tends to keep the evaporation of the electrolyte at a minimum. Fig. 1,154.—Edison Alternating Current rectifier; view with cover open showing parts. B, primary circuit cord; C, condenser; E, primary relay; F, secondary switch; S, alternating circuit switch; T, transformer. Fig. 1,155.—Vibrating unit of Edison alternating current rectifier. M, permanent magnet; N, carbon vibrating contact; O, comb radiator; P, primary circuit coil; Q, vibrator adjustment screw. Fig. 1,156.—Elementary diagram of connections.
Every battery room should be provided with a water tap and sink. The floor should be paved with vitrified brick, preferably blue or yellow in color, of diamond pattern and sloping in all directions toward suitable drains. A floor of this type can be easily washed by flooding with water, and its patterns tend to keep it dry under foot at all times. Wooden floors are rotted very quickly by acid spillings and by the spray. The room should be kept absolutely clear of everything, which may be injured, by the sulphuric acid fumes and it should be well ventilated to insure the safety and good health of the attendants. A battery, even at rest, gives off hydrogen which when diluted with air forms a mixture which is very liable to explode if brought in contact with any kind of flame. Unless proper ventilation be provided, the breaking of the connection when a current is flowing, or the lighting of a bare flame lamp in the battery room would be dangerous. Battery Attendants and Workmen.—Those employed in setting up batteries are liable to suffer from soreness of hands and the destruction of clothing unless proper precautions be taken to prevent the same. In order to avoid these troubles, the boots should be painted with paraffine mixed with an equal quantity of beeswax. The clothing should be of woolen material, which, unlike cotton, is practically unaffected by the acid. If cotton shirts be worn, they should be dipped in a strong solution of washing soda and then rough dried. An apron of sacking, backed with flannel should be worn over all the other clothes. A bottle of strong ammonia should be Fig. 1,157.—Interior of storage battery room showing arrangement of cells. A, are the cell insulators; B, wooden stringers; C, supporting pieces.
Points on Care and Management.—In setting up storage cells, they should be placed in as few tiers as possible, and in such a manner that the direct rays of the sun are not allowed to fall upon the cells. The rays of the sun are likely to crack the glass. This is probably due to the unequal expansion of the glass, for it has been found that jars which are carefully annealed never crack in this manner. Of course, the latter precaution does not apply to large batteries, where lead lined wooden tanks or solid lead boxes are used. In installing plants where expert attendance is not to be had, it is well to place in the circuit two magnetic cut outs, one set for maximum current, and the other for minimum voltage, so that the battery cannot be discharged too low. Ques. How should the cells be placed? Ans. They should be placed as shown in fig. 1,151, on insulators A, resting on wooden stringers B, and supporting pieces C placed on the floor. The insulators are usually of glass or porcelain, which in certain patterns may be filled with oil, to insure better insulation as shown in figs. 1,165 and 1,166.
Ques. How should the wooden stringers, shelves, cell boards, and trays be treated? Ans. They should be thoroughly varnished to insure cleanliness as well as good insulation.
Ques. What should be done to avoid waste of current by leakage? Ans. Each cell of the battery must be thoroughly insulated. Ques. What is the effect of verdigris which forms on the terminals? Ans. It is a poor conductor and should therefore be removed and the terminals kept bright and clean to insure the proper flow of the current. Fig. 1,158.—Charging "Champion" battery with charging plug. Where direct lighting current is available, recharging may be done by means of the charging plug. First insert the plug in a regular socket. Then screw a 50 c.p. lamp into the plug and turn on. To tell the positive from the negative, lay both wires on a small piece of red litmus or test paper moistened. The negative wire makes a mark on the paper. This wire must go to the negative post of battery. This will fully charge the "6-25-G" battery in 15 to 20 hours. Ques. What precautions should be taken in unpacking cells? Ans. The plates should be handled carefully. When they are sent out from the factory already built into sections, they
Figs. 1,159 to 1,161.—"Champion" electric light equipment designed especially for use on launches, yachts, and country residences. The outfit consists of three essential parts: 1, a dynamo run by belt from main engine; 2, a storage battery, and 3, a switchboard to regulate, measure and control the current. Ques. How should the cells be assembled? Ans. In placing the plates or plate sections in the containing jars or tanks, care should be taken to see that the supporting frame of paraffined wood bears evenly on the bottom of the jar. If they do not, wedges of paraffined wood should be placed under the frame, so as to distribute the weight of the section equally. Each section should be lowered gently into the jar until it rests fairly upon the frame, and care should be taken to see that none of the plates have shifted, and that the section is situated centrally in the jar, with a small clear space all around. Ques. How should the cells be arranged? Ans. They should be so placed that the battery attendant can see the edges of the plates and consequently the spaces between them at the same time. Ques. Describe the method of connecting the cells. Ans. This is accomplished by means of solder, bolts and nuts, or clamps, according to circumstances. The use of solder is not essential if there be a good surface of the lead strip of one cell in contact with that of the next, and provided these contact surfaces have been well cleaned. Usually, the ends of the lead strips are turned up so that the junction of two cells takes the form of an inverted T as shown in fig. 1,162. Fig. 1,162.—Two storage cells; view showing the inverted T form of connection. Ques. What precaution should be taken in joining the terminals of the cells? Ans. The contact at the junctions should be very thorough, otherwise they will become heated when a current is flowing, and
Cell Connections.—The cells may be connected together either in series or parallel, or in parallel-series or series-parallel combinations, according to the requirements, but in all cases it is best to use the simplest arrangement practicable.
Battery Troubles.—To successfully cope with faults in storage batteries, there are two requisites: 1, a thorough knowledge of the construction and principle of operation of the battery, and 2, a well ordered procedure in looking for the source of trouble. The faults which are usually encountered by those who operate storage batteries are here given. Fig. 1,163.—Arrangement of battery cells and stand. A, cable lugs; B, bus bars; C, glass tanks; D, plate; E, glass insulators; Q, vitrified brick; O, lead washers. Battery cells are set up on stands; the one shown being built for a 100 ampere battery. Larger sizes would, of course, require heavier stands, and if space be limited, the cells may be set in rows, one above the other. However, it is evidently much better to place the cells in single rows, where they will be convenient for inspection and repairs or any work that has to be done on them. There are several other ways of setting a battery, one of which is to place the stringers on the floor, on vitrified brick or some other insulator, and then place trays filled with sand on the stringers, setting the cells in the trays on glass insulators. The battery room should be dry, clean, well ventilated and free from metal work, also neither too hot nor too cold. Too high a temperature in the battery will shorten the life of the plates, and although there is no danger of the battery freezing, a low temperature, while it is maintained, reduces the capacity; otherwise cold has no ill effect on the battery. A good temperature for the battery room is about 60° F. A damp, dirty room is conductive to grounds and surface leakage, and there is danger of impurities getting into the cells. If the room be very damp the electrolyte may absorb enough moisture to cause the cells to overflow. Strong floors are necessary to support a battery, as one of a 100 ampere, 125 volt capacity weighs from 12 to 13 tons. A wood floor may be used, but a cement floor is better, and a glazed vitrified brick floor is better still. Wooden floors will rot quickly from the acid, which is sure to get onto it more or less; a cement floor will be disintegrated if too much acid get onto it. This kind of floor forms a first class ground if there be any chance for one; the glazed brick floor is not affected by the acid and is an insulator. Short Circuiting.—A form of derangement that may occasionally affect storage batteries is short circuiting. It may be caused by some of the active material—if the cell be of the pasted variety—scaling off and dropping between the plates, or by an over collection of sediment in the bottom of the cell.
A cell that has been short circuited may be disconnected from the battery and charged and discharged several times separately which may remedy the trouble. Ques. How are internal short circuits indicated? Ans. Short circuits in a cell are indicated by short capacity, low voltage and low specific gravity, excessive heating and evaporation of the electrolyte. Ques. How are internal short circuits located? Ans. If the trouble cannot be located by the eye, the battery should be connected in series and discharged at the normal rate through suitable resistance. If a suitable rheostat be not available, a water resistance may be used.
Overdischarge: Buckling.—On account of unequal expansion of the two sides of a plate, or certain portions thereof, the strains thus set up may distort it and cause it to assume a buckled shape, that is, bent so one side is concave. Fig. 1,164.—Method of straightening a buckled plate. Buckling is caused by the unequal expansion of the plates which is due to the sulphate lodging on the plates, thus preventing action taking place at that point; and by excessive charging. If the plates be not badly buckled, they can be placed between 2 boards and with a little pressure, can be straightened out.
Sulphation of Plates.—During discharge a storage cell deteriorates on account of the formation of lead sulphate over the surface of the plates. This lead sulphate is the product of the Figs. 1,165 and 1,166.—Oil Insulator; fig. 1,165, general view; fig. 1,166, sectional view. Whenever a number of open cells are in use, unless precautions be taken, electrical leakage between the cells invariably occurs. This leakage is due chiefly to the semi-conducting nature of the thin layer of moisture which frequently covers not only the glass containing cells, but the unimmersed parts of the elements, and even the shelves on which the cells rest. To prevent this waste of energy, the outside of the cells should occasionally be well cleaned and thoroughly dried. A little vaseline or tallow may then be rubbed over them to advantage. The shelves or supports for the cells, should either be well varnished or coated with paraffin wax. Electrical leakage is greatly reduced if each cell be mounted on a glass or earthenware insulator, as shown in the illustrations. The insulator here shown is in two parts and of a mushroom shape. The lower cup contains a small quantity of some non-evaporating oil, and as the conducted moisture cannot bridge across this, a nearly perfect insulating medium is obtained. These insulators are made in various sizes and may be obtained in earthenware or glass. Those made of glass are found to give the best results. Ques. Name some causes of sulphation. Ans. It is sometimes caused by a too weak or too strong acid solution, but more generally by continued over discharging, or too rapid discharging of the batteries, or by allowing them to remain uncharged for long periods of time. Ques. What is the effect of sulphation? Ans. It tends to cause shedding of the active material, buckling of plates, loss of capacity, increase of resistance and consequent reduction of efficiency, and increase of temperature with Fig. 1,167.—Illustrating method of placing plates in glass jars. Ques. What should be done in case of sulphation? Ans. Charge the battery below the maximum rate, necessarily prolonging the charge, until the plates assume the proper color. This is a tedious task, but it must not be hastened, as rapid charging will cause serious buckling.
Lack of Capacity.—This is usually due to the clogging of the pores in the plate with sulphate which is invisible because the surface of the plate is maintained in proper condition but the
Ques. What action takes place when a battery stands idle for some time? Ans. It loses part of its charge, due to local losses in the cells. Ques. How should batteries be treated, when used but occasionally? Ans. If a battery is not to be used for several days, it should first be fully charged before standing; if it continue idle, a Ques. What should be done in case of lack of capacity? Ans. If the current consumption be normal, there may be poor connections or trouble in the battery; there may be a dry cell, due to a leaking jar; some or all of the cells may be in a state of incomplete charge, due to the battery having been run too low and not sufficiently charged, or the plates may be short circuited, either by the sediment (deposit in the bottom of the jar) getting up to the bottom of the plates or by something that has fallen into the cell.
The current may be regulated by altering the distance between the plates or by varying the strength of the solution. As the discharge progresses, the voltage will gradually decrease and it should be frequently read at the battery terminals. When it shows a sudden drop, the voltage of each cell should be read with a low reading voltmeter. While the readings are being taken, the discharge rate should be kept constant and the discharge continued until the majority of the cells read 1.70 volts; those reading less should be noted. The discharge should be followed by a charge until the cells which read 1.70 volts are up; then the low cells should be cut out, examined and the trouble remedied.
Ques. What causes low specific gravity when there are no short circuits? Ans. 1, sloppage or a leaky jar (the loss having been replaced with water alone), 2, insufficient charge, 3, over discharge, or 4, a combination of these abuses. Any of these mean that there is acid in combination with the plates.
Figs. 1,169 and 1,170.—The "National" storage battery; views showing methods of assembling cells. Fig 1,169, end assembling; fig 1,170, side assembling. Ques. How should weak cells be treated? Ans. They should be grouped by themselves and charged as a separate battery, care being taken that the positive strap of one cell, is connected to the negative strap of the adjoining cell and
Figs. 1,171 to 1,177.—"National" battery bolt connector and parts. The connector is equipped with grease cups and antimonious lead washers. Disconnecting Cells.—The best method of disconnecting cells assembled with pillar straps, for the purpose of replacing broken jars, cleaning or taking out of commission, is to use a five-eighth inch twist drill, in a carpenter's brace, boring down into the top of the pillar about one-quarter inch; then pull off the connector sleeve from the pillar. By following this method, all parts may be used again.
Taking Batteries out of Commission.—Where a battery is to be out of service for several months, and it is not convenient to give it the freshening charge every two weeks, it should be taken out of commission.
Ques. Describe the method of taking a battery out of commission. Ans. The battery is charged in the usual manner, until the specific gravity of the electrolyte of every cell has stopped rising over a period of one hour (if there be any low cells, due to short circuits or other cause, they should be put in condition before the charge is started, so that they will receive the full benefit of it). The cells may now be disconnected and covers and elements removed from the jars, (if sealed, the compound is loosened with a hot putty knife). The elements are placed on their sides with the plates slightly spread apart at the bottom, the separators withdrawn, and the positive and negative groups pulled apart. The electrolyte is washed off with a gentle stream of water and the plates allowed to drain and dry.7
Fig. 1,178.—The "Witham" charging board, for charging from any electric outlet on a direct current system. The instrument shows the direction of the current, and the candle power of the lamps used as resistance indicates approximately the strength of the current passing. Operation: From any convenient electric light fitting remove one of the lamps, replacing it by the plug attached to the flexible cord. Screw the lamp into one of the sockets on the charging board. Connect a wire to each binding post, and before joining up to the battery, hold the ends of the two wires together. The lamp will then light up and the indicator needle will point to that binding post which must be connected to the positive (+) terminal of the battery. The other binding post must, of course, be connected to the negative (-) of the battery. The charging current can be increased by inserting another lamp into the second socket on the charging board and by using lamps of higher candle power. If, when the lamp lights up, the indicator needle do not point to one of the binding posts, but retain its position midway, then the current is an alternating one and will not charge the battery. Ques. What precaution should be taken with the jars? Ans. They should be thoroughly cleaned with fresh water, no sediment being allowed to remain. Putting Batteries into Commission.—When re-assembling a battery, it should be treated in the same manner as if it were new and the regular instructions for assembling and putting a new battery into commission followed. Cleaning Jars.—The jars should be thoroughly cleaned with fresh water, no sediment being allowed to remain.
Condensed Rules for the Proper Care of Batteries.—The following general instructions should be followed in the care and maintenance of batteries:
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