An arrangement for testing electric batteries of vehicles, said arrangement comprising: a test system (TS) and at least two test chambers (111-116) for the electric batteries to be tested, an infrastructure module that is a transportable container accommodating test system equipment (FC) arranged to input charge cycles and/or discharge cycles to the vehicle batteries at two or more test modules (121-126) and, further, a frequency converter, and the two or more test modules (121-126) each comprising a transportable container (131-136) comprising a test chamber for the electric batteries ( C ) to be tested, test system connection elements (CE1, CE2) for operatively connecting the test system equipment at the infrastructure module to the two or more test modules (121-126), a climate control system configured to adjust environmental conditions in the two or more test chambers during the testing, characterised in that the two or more test modules (121-126) accommodate a humidifier of the climate control system, wherein the transportable container of the infrastructure module further accommodates at least a water filtering device of the climate control system and a fire safety system, wherein the two or more test modules (121-123, 124-126) are arranged next to the transportable container of the infrastructure module on different sides of the infrastructure module so that the infrastructure module is between the test modules (121-126), and wherein the arrangement further comprises a climate control system connection element (CE2) to produce filtered water from the water filtering device to the humidifiers in the test modules (121-126). a test system (TS) and at least two test chambers (111-116) for the electric batteries to be tested, an infrastructure module that is a transportable container accommodating test system equipment (FC) arranged to input charge cycles and/or discharge cycles to the vehicle batteries at two or more test modules (121-126) and, further, a frequency converter, and the two or more test modules (121-126) each comprising a transportable container (131-136) comprising a test chamber for the electric batteries ( C ) to be tested, test system connection elements (CE1, CE2) for operatively connecting the test system equipment at the infrastructure module to the two or more test modules (121-126), a climate control system configured to adjust environmental conditions in the two or more test chambers during the testing, characterised in that the two or more test modules (121-126) accommodate a humidifier of the climate control system, wherein the transportable container of the infrastructure module further accommodates at least a water filtering device of the climate control system and a fire safety system, wherein the two or more test modules (121-123, 124-126) are arranged next to the transportable container of the infrastructure module on different sides of the infrastructure module so that the infrastructure module is between the test modules (121-126), and wherein the arrangement further comprises a climate control system connection element (CE2) to produce filtered water from the water filtering device to the humidifiers in the test modules (121-126). <EOS>