A Tester for Batteries.
Page 65
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TO obtain the best service from an electric storage battery it is essential that it should be kept in perfect order. The usual method of testing is by means of a pocket voltmeter on open circuit, which is not only useless but misleading, for the reading of even the most defective cell will approximate to two volts after standing. This was emphasized in an article dealing with the proper treatment of batteries which was included in a recent issue; To form an opinion as to the state of a cell without first dismantling it for inspection, it is necessary to subject it simultaneously to a heavy rate of dis
charge and a voltage test. The voltage varies within very definite limits in relation to the current discharging, and an undue drop can be taken as a positive indication of serious trouble. It is thus possible to isolate a particular cell in a battery of, say, 6 volts or 12 volts, as being defective ; consequently, the time and expense involved in the opening of all the other cells are saved.
With a view to meeting these requirements the Runbaken Magneto Co-, Tipping Street, Ardwick, Manchester, and 75, Gt. Portland Street, London, W.1. has brought out a new battery tester in which the meter reads both in volts and
amps. A load up to 250 amps, can be applied while making the test, and, a small inspection lamp is provided which, in addition to lighting up the face of the meter, gives an indication of the state of the cell. This feature is vain-able, as it permits pointing out the faults in a convincing manner to the uninitiated.
The meter is of the moving-coil type, of robust make and with prongs of hardened nickel-steel which can readily be renewed ; in fact, the whole instrument is built to withstand rough usage. Its price is 59s. 6d., or in a cheaper form with magnetic meter, 39s. 6d.