8. Remember that if you have a line only partly full and have other batteries waiting to be charged you are losing money by not keeping a full line.
9. Leave the Vent Plugs in When Charging. The atmosphere in many service stations, where the ventilation is poor, is so filled with acid fumes that customers object to doing business there.
The owners of these places may not notice these conditions, being used to it, or rather glory in being able to breathe such air without coughing or choking, but it certainly does not invite a customer to linger and spend his money.
The remedy for such a condition is to leave the vent plugs in place on the batteries that are charging so that the acid spray in the gas from the battery condenses out as it strikes these plugs and drips back into the cells, while the gas passes out through the small openings in the plug.
The plugs need only be screwed into the openings by one turn, or only set on top of the vent openings to accomplish the result.
This takes no additional time and more than repays for itself in the saving of rusted tools and improved conditions in the battery room and surroundings. In charging old Exide batteries, be sure to replace the vent plugs and turn them to open the air passages which permit the escape of gases which form under the covers. If you wish to keep these air passages open without replacing the plugs, which may be done for convenience, give the valve (see page 21) a quarter turn with a screwdriver or some other tool.
10. If the electrolyte from a battery rises until it floods over the top of the jar, it shows that too much water was added when the battery was put on charge, the water rising to the bottom of the vent tube, thereby preventing gases formed (except those directly below the vent hole) from escaping. This gas collects under the covers, and its pressure forces the electrolyte up into the vent hole and over the top of the battery. In charging old U.S.L. batteries it is especially necessary to keep the air vent (see page 20) open to prevent flooding, since the lower end of the vent tube is normally a little below the surface of the electrolyte.
Remember, do not have the electrolyte come up to the lower end of the vent tube.
NOTE: To obtain satisfactory negative cadmium readings, the charging rate should be high enough to give a cell voltage of 2.5-2.7.
Improperly treated separators, or separators which have been allowed to become partly dry at any time will make it impossible to obtain satisfactory negative cadmium readings.