Did they ever fix the battery drain issue?

Yes, the issue still stands. I was only charging once every 2 weeks or so. Now I have to charge every 6 hours and I can barely get through one Strava recording. 

Not that it would really help you, but during the past year I have the same battery life - charging the watch about every two or three weeks (depending on number of GPS activitities). I have a habbit of restarting the watch after every charging session (or PC data transfer) - no idea if it fixes anything, but certainly doesn't hurt. 

I see a lot are having this issue. This started happening to me 3 days ago too! 

My current strategy is to leave my watch switched off and unused, until I do a ride (every second day). Then I charge it to 100% just to get through one event. It’s pointless to wear the watch for any other reason as the battery drains to zero in around 6 hours. 

My current concern is that complete battery discharge occurs even when the watch is off. Is OFF merely a sleep mode then and the operating system is still active?

PeterZA said:

My current concern is that complete battery discharge occurs even when the watch is off.

That sounds like a faulty battery. Contact the support.

I am just extremely unlucky that this happened a week after my 1 year warranty expired? 

PeterZA said:

I am just extremely unlucky that this happened a week after my 1 year warranty expired?

I'd tell yes, you are. My Instinct 1st gen is all right after almost 4 years, and generally I do not see many reports about complete battery failure like yours, here on the forum. There are frequent complaints about the battery gauge that often shows wrong battery level after a firmware update, but that usually gets sorted out after a watch reset, or after a full charge / full discharge cycle. Also some people do not realize that for example the PulseOx feature is quite power-hungry, especially if set to the all-day mode.

However, that does not seem to be your case. Either it is a battery failure, or a water leak discharging the battery even when off. To exclude software issue, I'd suggest performing the reset of the watch (holding the Light button till the watch shuts down), and if no help, then the master reset to factory defaults. If nothing helps, contact the Support. If your watch is really just a week after the end of the warranty, then they may perhaps accept replacing it anyway.

I had exactly the same problem when I bought my Instinct Solar just under 2 years ago. Battery life was only about 3 days and Garmin replaced it under warranty when it as few weeks old. The replacement battery life was very good until recently. For me it is not a battery drain issue but that the watch switches off regularly, even when the battery is apprently above 50%. The watch is becoming useless for activity tracking (mainly cycling). Examples of when it shuts down include:

• when an alarm (set on the watch) goes off
• when starting an activity, or during it, either with or without the GPS;
• taking a manual SPO2 reading

I'm not sure whether it is just the battery deteriorating or its a firmware problem (currently 18.1). I had a similar problem with one of my previous phones as it got old and the battery deteriorated: the high power draw when you activated the camera just caused it to shut down. A lithium battery should last far more more than 2 years, especially as it has only needed to be charged every week or 2, so less than 100 charge cycles, 

Just this morning I checked the battery status before I started a cycling activity and it was 55% (16d). Just after the GPS got lock the watch just went blank. When I managed to restart the watch later the battery was srill 55%.

The battery is still good on my 5 year old Garmin Forerunner 35, so I'll have to revert to that.

Think it is a software issue. Mine was doing exactly the same. Sent my watch back, waiting to hear the outome.