Maybe this here would be an approach that would work: Gas meter from Xiaomi/Aqara door sensor (ZigBee)
p.s.: battery life probably heavily depends on the number of pulses. To give you an idea: I’ve got the aqara sensor as an actual window sensor, and with i guess a dozen pulses per day, the battery is at 73% after 1.5 years of usage. So depending on how that meter translates power to pulse frequency, and how cold it gets in the outside box, you might want to upgrade the power source to AA batteries