Load testing of batteries is used to verify that the battery can deliver its specified power when needed. At TPS we supplement the actual load with a load bank, to control the desired discharge rate. The AC load bank is connected to the output of the inverter, while batteries power the inverter. This test will exercise the batteries and the UPS. Battery load testing is the least expensive way of testing your batteries. Even though these test results will not help determine the actual battery capacity, these results will at least serve the following purposes.
Identify faulty batteries in the circuit
Determine if the battery is capable of supporting the connected load for the specified time
Determine the integrity of the battery system
Battery load testing has four phases:
1. Preparation -Phase 1
At TPS, we recommend testing batteries only when they were under float continuously for 48 hours. We perform all 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 satisfactory, 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 the 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.
3. Restore -Phase 3
Disconnect all load test cables and connect batteries back to the power system for charging
4.Reporting – Phase 4
Analyze test results, prepare summary, and flag any failed batteries. If batteries exceeded 80% of the nominal backup time, batteries have passed; otherwise, batteries have failed.