The battery-box is the power supply of the AD-box and Active electrodes. The battery-box contains a sealed lead-acid battery and a shutdown circuit to prevent the battery from deep discharge. The combination of a large capacity battery and very low power consumption of the AD-box and Active electrodes makes the ActiveTwo the only real battery powered, high number of channel system. In 256 channel version battery life is at least 5 hours, less channels offer extended battery life, up to 3 days for a 16 channel version. Given the charge time of less than 4 hours, continuous longtime measurements are possible with the 2 standard provided batteries. (Battery can be changed in less than 10 seconds. Double capacity batteries are available for users needing double battery live.

Optionally, the BioSemi acquisition software can detect whether a battery is replaced by another battery. When the second battery is connected to the amplifier within 30 seconds, the acquisition will resume normally.