Since the charging rates of these rectifiers are fixed to two values, 12 amperes and 24 amperes, depending upon whether one or both rectifiers are used at a time, the time required for charging is pretty well fixed for a particular condition of discharge. A charging rate of 24 amperes should not be used when the battery is gassing freely. A charging rate of 24 amperes should be used only when there is some one present who can periodically check the condition of the battery. The battery should not be charged at this high rate for long periods of time or overnight, as over-charging (particularly at a high rate) quickly ruins the plates. The 12 ampere rate should always be used when there is sufficient time to charge the battery at this rate. To determine the time required for charging the battery use the table in section 50.

If the bulbs fail to light when the AC line switch is "On," look for blown fuses in the AC line circuit. If these fuses prove to be O.K. and there is alternating current available at the charger, turn "Off" the line switch, remove the bulbs, and clean the socket and bulb contacts. Return the bulbs to their sockets and screw them in securely. Make sure that the clip that fastens to the top connection of the bulb makes good contact. If the bulbs still fail to light, try one that is known to be O.K.

The Tungar charger shown in Figure 44 has separate controls and an ammeter for each bulb. To operate, see that both the regulator knobs are turned to the "Off" position by turning them to their extreme counter-clockwise position. See that the snap-switch on the charger is in the "Off" position. Connect the battery to be charged by means of the four-pole change-over switch. Turn the snap-switch on the charger panel to the "On" position and turn the regulator handles to give the desired charging rate. The regulators should be adjusted so that the readings on both ammeters are approximately equal. The charging current is the sum of the two ammeter readings. The ammeters should not read above 6 amperes each, for normal operation. They will operate satisfactorily at 7 amperes, but this higher charging rate will considerably shorten the life of the bulbs.

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