Any battery system needs control and testing because problems can arise before the life expectancy of the battery. There are many reasons why the general battery system should be tested:

Charger adjustments. Incorrect charge can reduce the life of the battery.   Tension between cells can be different, so charging to level them may be needed.   Corrosion on edges or internal parts.   Leaks.  Outside temperature.

Usually, battery testing is done monthly, every three months or annually. In general testing, the battery is connected for regular use and a number of factors are measured: outside temperature, total tension between poles, exit tension of the charger, density and temperature of electrolytes, water consumption and resistance.