I have 2 of the same.
One is placed where we there are frequent movements a passage where we constantly pass.
The other one in the basement where we pass only occasionally 2 - 5 time per week.
The first one gets drained in 2 -4 month but the second one in the basement lasts for one year or even longer.
In my case it seems to be the motion sensor activity that drains the battery.
I am definitely looking for an alternative replacement.