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.
For instance: if the cells employed in an installation requiring 110 volts, have only half the capacity required, and 55 cells give the desired voltage, then the number of cells must be increased to 110, and theoretically the required number of amperes hours at 110 volts may be obtained in one of two ways: 1, by connecting the cells in pairs in parallel and then coupling the pairs together in series, and 2, by arranging the 110 cells in two complete batteries of 55 cells each connected in series, then coupling the two batteries in parallel.
The first method is quite impracticable, however, as the slightest difference between the voltages of the two cells of any pair will result in the one having the greater pressure discharging into the other, thereby causing the entire battery to quickly deteriorate.
NOTE.—To determine the positive wire. Without a voltmeter, the positive terminal of the charging circuit can be determined by attaching a piece of clean lead to each wire which is to be connected to the battery, and immersing them, without touching each other, in a glass or other insulating vessel containing water to which is added a drop or two of sulphuric acid. After the current has passed through the circuit for a short time, the positive lead will commence to discolor, and, if left long enough, will turn brown. Bubbles will arise from the two terminals immersed, the larger and more frequent ones being from the negative, the smaller ones from the positive.
NOTE.—Method of disconnecting "National" cells. There are two methods of disconnecting the cells employing link connectors. First a ⅝ inch bit or twist drill may be used, boring down into the top of the posts about ¼ inch. The link will then be loosened and can be removed. This leaves the link, as well as the post, in good condition for reburning. Second the link may be cut in the center. A flame should be played on the top of the post, at the same time grasping the end of the half link firmly with pliers. When the connection has become warmed (care being taken not to melt the lead) the half link can be twisted loose from the port. New links may be used if desired in re-assembling the cells. It is not necessary to remove the covers from the element, the links may be cut in the center and the plates removed from the jars without removing the links from the ports. The links can be afterwards reburned together in the center. When the cells are equipped with "T" or "L" straps, they should be cut apart with hack saw or chisel midway between the cells, and in re-assembling, burned together at this point.
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.
Should the operator suspect trouble with his battery he may discover a short circuited cell by the marked difference in color of the plates or of the specific gravity of the electrolyte, as compared with the other cells. No particular damage will be caused, if the trouble be discovered and removed before these symptoms become too marked.
If a foreign substance has become lodged between the plates, it may be removed by a wood or glass instrument.
If some of the active material has scaled off, it may be forced down to the bottom of the jar. If excessive sediment be found, the jar and plates should be washed carefully, and reassembled.
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.