1. If it is the battery of the gas meter, the appearance is clearly marked and the battery is installed inside. Some may be on it, and some may be under the LCD screen. Generally speaking, it is fixed with screws. So we need to prepare a screwdriver. Loosen the screw first, and we can see that there are four batteries in it, all of which are size 5. Generally speaking, the batteries will be replaced after two to three months of use. Just take down the old battery and put it back according to the correct installation method of the positive and negative electrodes.
2. If it is a gas meter, it is generally at the bottom. We can turn the gas meter upside down and see if there is a battery level. After finding it, open the battery cover again. There are dry batteries in it, and they are big batteries. It may take one or two, then take it off, put it back and put the lid on it.