Battery Maintenance Testing

Battery Testing

Credits: NETA/NFPA

Field Testing in General.?The stationary battery technologies predominantly in use today are vented lead acid (VLA), valve regulated lead-acid (VRLA), and nickel-cadmium (Ni-Cd), and are the types addressed in this document. The applicable industry maintenance standards include the following:?

(1) ANSI/NETA ATS,?Standard for Acceptance Testing Specifications for Electrical Power Distribution Equipment and Systems?

(2) ANSI/NETA MTS,?Standard for Maintenance Testing Specifications for Electrical Power Distribution Equipment and Systems?

(3) ANSI/IEEE 450,?Recommended Practice for Maintenance, Testing and Replacement of Vented Lead-Acid Batteries for Stationary Applications?

(4) IEEE 1188,?Recommended Practice for Maintenance, Testing and Replacement of Valve-Regulated Lead Acid (VRLA) Batteries for Stationary Applications?

(5) IEEE 1106,?Recommended Practice for Installation, Maintenance, Testing, and Replacement of Vented Nickel-Cadmium Batteries for Stationary Application?

Battery Tests.?

Tests should be performed and the results recorded to establish trends that can be used in predicting state of health. The type of data to be collected will depend upon the battery technology being used. Table 1 shows examples of data that can be collected, but it is not a comprehensive list. For trending state of health, a baseline should be established approximately six months after the battery has been put into service, or two weeks after the most recent discharge, whichever is later.?

1 Voltage, Temperature, and Specific Gravity.?If used, pilot cell/block voltage, specific gravity, and electrolyte temperature should be measured and recorded at every maintenance interval.?Refer to the manufacturer’s recommended practices for the use of pilot cells or blocks and for the range of float voltage applicable to a specific battery.?

1.1???Temperature Testing.?Pilot cells can be selected to obtain a representative temperature and to detect temperature gradients within a string. Temperatures should be collected for no less than 10% of the units in a string. For VRLA batteries, cell temperature should be obtained by measuring at the negative post of the unit. For vented batteries in which electrolyte samples are being collected, electrolyte temperature can be determined at the same time.?

Figure 1

Data Collection for Trending Battery State of Health

1.2 Electrolyte Sampling.?Where electrolyte sampling is used, refer to the manufacturer’s recommended practices for the use of pilot cells and for the range of float voltage applicable to a specific battery. It is advisable to periodically change pilot cells, because a slight amount of electrolyte can be lost each time a specific gravity reading is taken.?

1.3 Ohmic Testing.?If ohmic measurement is used for lead-acid batteries, it is recommended that ohmic measurements (resistance, impedance, and conductance) be collected, recorded, and reviewed at regular intervals, but in no case less than quarterly. Use of ohmic measurements should be in accordance with manufacturer’s instructions and with an established maintenance program to set baselines, to identify trends, and to identify anomalies. When anomalies are detected, additional steps, such as a capacity test or unit replacement, might be warranted.?

2 Performance Testing.??A performance test should be performed at intervals not greater than 25 percent of the expected service life as determined by the initial design, or as recommended by the manufacturer, depending on the load reliability requirements and environmental conditions of the installation. The frequency of battery tests should be increased to yearly when the battery reaches 85 percent of its service life or when it shows signs of deterioration.?

3 Connection Resistance.??Connection resistances of cell-to-cell (or block-to- block) and terminal connections should be tested in accordance with manufacturer’s instructions and with an established maintenance program. Where a test set to read intercell connection resistance is not available or cannot be utilized (for example, due to inaccessible posts), the infrared scan can be used to indicate which connections need to be torqued to the battery manufacturer’s specified values.??

4 InfraRed Scanning.?Batteries should be examined under full load with an infrared scanning device whenever a performance test is conducted. Infrared scanning can reveal problems such as abnormal temperature of a cell, a poor connection at a battery post, and a deteriorated link, strap, or conductor.?

5 Record Keeping.?Measurements should be recorded for future reference along with log notations of the visual inspection and corrective action. Measurements and inspections will vary from one type of battery to another.. The records should be modified to correspond to the user’s maintenance program.

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