The SI-100C and a range of associated Gas Detection Australia controllers can be used in battery room gas detection to detect hydrogen in battery rooms and sound alarms. The battery room gas detection systems comprise of a hydrogen gas sensor SI-100C and a gas sensor control unit. The Gas Detection Australia control unit GDA 4020 or GDA 4011 is situated external to the battery room to display the gas concentrations and the alarm status. The battery room gas detection system can then be interfaced to extraction fans, sounders or other apparatus. For smaller battery charging rooms the standalone GDA 40126 can provide an integrated sensor and controller with outputs to drive extraction fans and sounders.