In this paper, an automatic testing platform was developed. A complete charging and discharging cycle for the series-connected lead-acid batteries is carried out by the testing platform to record the capacity, charging efficiency, and other relative data of the batteries. A microcontroller unit (MCU) is used to replace the common DAQ card for cost reduction. The voltage and current of the batteries are sampled by the MCU and saved by the software LabVIEW on the personal computer. The charging and discharging procedures are automatically switched by the software LabVIEW according to the state of the batteries. A complete testing data can be provided by the LabVIEW at the end of the testing cycle. New and old battery modules are both tested with the proposed platform and another reliable testing system to evaluate the validity of the proposed system.