There are a number of different tests, recommended by IEEE, NERC and other standards for diagnostics of battery banks conditions. Two of the most commonly used methods to determine a battery's performance when required are the capacity test and the internal resistance test.
A battery discharge test, also known as a capacity test, is the only test that can accurately measure the true remaining capacity of a battery system and consequently provide insight into the operational condition of the battery.
To test the condition of a rechargeable battery, you will need the following tools: Multimeter – A multimeter helps measure voltage, current, and resistance. Battery tester/analyzer – A dedicated battery tester can provide more accurate readings. Battery charger – A charger is required for certain testing methods.
By measuring the voltage across the battery, its remaining capacity can be preliminarily estimated. The constant current discharge method is a more accurate battery capacity test method. Connect the battery to a certain load and discharge it at a constant current until the battery voltage drops to the predetermined cut-off voltage.
Interpretation: The hybrid method test result combines the Coulomb counting and voltage-based methods, yielding a measured capacity of 93 Ah and an SOC of 88%. By utilizing both methods, we can gain a more accurate understanding of the battery’s capacity and performance under the test conditions.
Well-developed battery test technologies must recognize all battery conditions and provide reliable results, even if the charge is low. This is a demanding request as a good battery that is only partially charged behaves in a similar way to a faded pack that is fully charged.