I noticed the battery drain issue from last week but the issue disappeared by itself. So I was confused whether it was just my memory goes wrong, so I started to record the battery life every morning when I woke up.
After a few days, I found my daily battery life usage was roughly 10%, more or less.
Now on Thursday, the battery was 81% when I woke up.
Afternoon I started a 56:42 Activity, the battery dropped to 61%. It makes sense because I was using an App called Komoot which was using all the sensors , All-system GPS, a real time map. So it was acceptable.
But on Friday, this morning, the battery life was 39% at 8am. Therefore I noticed something wrong happened again from yesterday. Then I downloaded a widget called Battery Graph for help me monitor the battery.
When it was 11 am, the battery remained 31%, which means I just sit in my office, no music no activity, the watch lost battery nearly 3% per hour.
At this speed to drain battery, for one day it will cause 3%*24 = 72% without any activity. Apparently it is abnormal.
So I searched the Internet and found some Garmin users mention the reason is GPS can't stop after activity.
I tried to search Venu 3 user manual, it only has how to change the GPS during activity, there is not any options in setting can show GPS status or disable the GPS!
So I found an other idea, to use the Weather App Settings, there is a option to update location information with GPS.
Usually, it would take a really long time to find the satellites because I was tried before, I was in my office and it took too long, I had to go out of my office to get signal.
However this time the watch updated the location instantly, that means the GPS never turned off!
After two times of updated the location, the watch back to normal, which means it needs to take a long time to turn on the GPS for satellites then try to update.
And then my watch's battery drain issue was better. You can see the difference from the graphic.
Currently I have no idea is the Komoot doesn't turn off the GPS before exit, or the OS doesn't release the GPS after activity.
I know the Garmin doesn't respond for the third party Apps performance. But the OS is designed by Garmin, also provide SDK for the developers, so Garmin should take over the resource control (or clean their mess) after the activities exit.
Also it would be nice if the watch has capability to view which sensors or feature is on or off, and manually disable them. So that user can find out what's going on and quick fixing issues, instead of complaint about the watch. Just like Windows has the Task Manager. Currently I don't see any in the setting. If there is one in somewhere I don't know. Please let me know.