I have the 44mm version, my wife the 40mm.
Both set up identical, Botg on same software. My wife's drains at about 10% or more an hour which is ridiculous.
The 44mm drains about 3% per hour.
I know the battery is different in the 40mm but this makes the watch virtually useless.
This drain is when not even using any tracking such as swimming or walking.
I've read there is an issue with some draining fast and it's a software issue. Any idea?