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Battery Capacity Testing
Battery systems must provide a reliable and stable source of DC power during a power outage, or whenever else it is needed. If your batteries cannot support for a sufficient time, or fail to support your critical applications, the purpose of having batteries is defeated. The only accurate method for determining the capacity or condition of a battery is to conduct a discharge test.
Battery capacity testing serves four main purposes:
Determine actual capacity of the battery
Determine if the battery is capable of supporting the connected load for the specified time
Identify faulty batteries in the circuit
Determine the integrity of the battery system
Battery capacity testing has four phases:
1. Preparation -Phase 1
At TPS, we recommend testing of batteries only when they were under float continuously for 48 hours. We perform all the aspects of preventive maintenance, such as visual inspection, conductance and voltage reading, and torque on all cells. We also make sure we have enough jumper cables.
2. Load Test - Phase 2
If Phase 1 results are satisfied, we disconnect the charger or input power to the unit and start testing. We closely monitor load current and record cell voltage continuously; we flag cells that are 25 millivolts below other cells and monitor these cells continuously. Once the cell voltage reaches 1.75 VPC we stop load test. If there were any cells that fell below 1.75 VPC during the test, we will halt the test for few minutes and jumper those cells. Alternatively, we offer a computer-controlled battery capacity testing system that confirms IEEE test methods in which all voltage and current levels are automatically recorded and trended. Computer-controlled testing is expensive when compared to traditional testing.
3. Restore -Phase 3
Disconnect all load test cables and connect a battery charger to charge the batteries for a few hours so the batteries can regain charge levels. After batteries reach charge level, connect batteries back to the system.
4.Reporting - Phase 4
Analyze test results, prepare summary, and flag any failed batteries. If batteries exceeded 80% of the nominal capacity, batteries have passed otherwise batteries have failed.
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