A programmable electronic load may be used to test rechargeable batteries and determine discharge characteristics. Since a programmable load can produce a constant current drain regardless of battery terminal voltage, testing batteries is very reliable. Many modern programmable loads feature built-in battery testing algorithms that make testing and characterization of rechargeable batteries a simple matter.
Any electronic load may be used to test various batteries, but may require close supervision or a custom automated test program. The Circuit Specialists CSI3721A is ideally suited for testing rechargeable battery packs of many different chemistries — including lithium-ion — because you can set the discharge termination voltage in order to avoid discharge below the safe voltage limit, allowing unsupervised discharge of the battery pack under test.
Listed below is the sequence of operations for testing and characterizing all types of rechargeable batteries:
1. Power on the electronic load and press the input on/off button to disable the load and then connect the battery pack while observing polarity.
2. Press and release the 2nd button before pressing the 6th (battery) button to enter battery discharge mode.
3. Press the “set” button and enter the desired discharge parameters using the up and down buttons to select the parameter, and the left and right buttons together with the rotary knob or numeric keypad to enter desired values for termination voltage and discharge current.
4. Press the “clear” button to exit the parameter entry screen.
5. Press the input on/off button to begin the automatic battery discharge test.
6. The electronic load will proceed to discharge the battery at the discharge current value set in step 3 and will automatically stop the discharge test of the battery when the battery voltage equals the set value. You may then view the elapsed time required to discharge the battery and the amp per hour rating of the battery on the LCD screen.
7. Press and release the 2nd button and then press the 6th (battery) button to exit battery discharge mode.
The specifications for the type of battery under test should be consulted to aid in the selection of the appropriate discharge current rate and termination voltage. These values will vary depending on battery chemistry.