Problem: Need to test Li-ion batteries inexpensively
Battery tester needs:
Ability to run tests over hundreds of cycles
Independent data logging, i.e. not tethered to a computer
Storage of test parameters in EEPROM
Flexibility in test options and battery sizes
Scalability so that many test units can be fabricated and operated
To address this problem, I designed and fabricated a distributed multi-cycle testing platform for long-term battery deep cycle testing. This test-rig was developed to cycle lithium-ion batteries over hundreds or thousands of cycles and logs data directly to a SD card in a csv format. The system is controlled using an Arduino microcontroller, and is programmed with all of the relevant test criteria. The test criteria is stored in EEPROM on the Arduino, so that the system will continue to operate normally in the event of power loss to the micocontroller. Otherwise, unplugging the system would reset the test parameters, cycle number etc… and would necessitate re-programming the micro and storing the incomplete test data. The system is designed to also fail in a safe condition in the event of power loss (i.e. the battery will not be shorted). The system is also designed to be used with LabView for real-time battery data monitoring. This allows for test parameters to be varied in real time while data is being displayed, which helps in determining system parameters for untested batteries.
Bill Bradford greatly assisted in this project and did much of the work designing the PCB layout, parts selection, fabrication and debugging of the PCB.
Parts list, and code files are available by request.