We have just seen that the charging rate of a 60-ampere hour battery is 7½ amperes. Applying Ohm's Law here, we find that ohms resistance equals volts divided by amperes, or R = 110/7.5 = 14.67 ohms. With a 220-volt current, the ohms resistance required in series with the storage battery of this size would be 29.33 ohms.
Automobile Power for Lighting
There are many ingenious ways by which an automobile may be utilized to furnish electric light for the home. The simplest is to run wires direct from the storage battery of the self-starting system, to the house or barn, in such a way that the current may be used for reading lamps in the sitting room. By a judicious use of the current in this way, the normal operation of the automobile in the daytime will keep the battery charged for use of the night lamps, and if care is used, such a plan should not affect the life of the battery. Care should be used also, in this regard, not to discharge the battery too low to prevent its utilizing its function of starting the car when it was desired to use the car. However, if the battery were discharged below its starting capacity, by any peradventure, the car could be started by the old-fashioned cranking method.
Using an automobile lighting system for house lighting implies that the car be stored in a garage near the house or barn; as this battery is too low in voltage to permit transmitting the current any distance. One hundred feet, with liberal sized transmission wires is probably the limit.
That such a system is feasible is amply proved by an occurrence recently reported in the daily papers. A doctor summoned to a remote farm house found that an immediate operation was necessary to save the patient's life. There was no light available, except a small kerosene lamp which was worse than nothing. The surgeon took a headlight off his car, strung a pair of wires through a window, and instantly had at his command a light of the necessary intensity.
Another manner in which an automobile engine may be used for house lighting is to let it serve as the charging power of a separate storage battery. The engine can be belted to the generator, in such a case, by means of the fly wheel. Or a form of friction drive can be devised, by means of which the rear wheels (jacked up off the floor) may supply the necessary motive power. In such a case it would be necessary to make allowance for the differential in the rear axle, so that the power developed by the engine would be delivered to the friction drive.
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