General Aspects of Battery Maintenance

The required maintenance operations may be different with different battery types, and sometimes the differences in regulation operations may be very substantial. In any case, these operations must never deviate from those specified for each battery type. In this section we discuss only some general aspects of maintenance. 

With the exception of sealed storage batteries, the main element of maintenance is the control of the amount and concentration of the electrolyte. When the electrolyte 

In order to compensate for partial decomposition of water because of overcharge and corrosion, water must be regularly added. Normally addition of acid or alkali solutions is inadmissible as the resulting increase in electrolyte concentration impairs battery characteristics. Only deionized water (if unavoidable, pure rainwater or melted snow may be acceptable) is to be added to the electrolyte. This water must not be kept in metal containers as even very small amounts of iron ions (or ions of other metals) introduced into the electrolyte are very harmful to batteries. Chloride ions present in normal tap water are also very dangerous. It should be kept in mind that boiling of water does not remove either chloride or iron ions. When water is added, the electrolyte must come to the level indicated in the manual for each specific battery (usually it is 3-5 mm above the upper edges of the plates). A certain time is required for the concentration to level off in the bulk of the electrolyte. 

The electrolyte concentration should be periodically checked. Sometimes it has to be corrected by adding an acid or alkali, for instance, after spilling part of the liquid or after prolonged charges (in the last case gases carry away tiny droplets of the electrolyte fog). Sometimes the electrolyte concentration is changed in the transition from summer to winter conditions of operation (or vice versa). 

The conditions in which batteries are stored must also satisfy certain requirements. Again, batteries must be clean, and especially their venting holes. Unfilled batteries must be stored with plugs tightly screwed. It is advisable to store unfilled lead acid batteries and all alkaline batteries in discharged state. Electrolyte-filled lead acid batteries should be stored after charging them to completion. 

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