Battery Life in Smartwatch Mode

I have been very disappointed as well.  I just contacted customer support and the immediately asked that I send it in to Garmin to be exchanged for a new one.  

I just contacted customer support and they instructed me to return it for a new one. I will be shipping it to garmin this afternoon.  Luckily I still have my 935 to use until the new on arrives. Though based on all these battery comments, I am not confident that this will correct the problem. 

I think I didn't charge the 935 to 100% when I gave those number.

But I did charge it again yesterday... and now around 17 hours and I've lost only 4%. Which is 2% more than 935 in the same time, but the 2% difference can be easily explained with the notifications and BT-communication with mobile.

Calculating from this it would give about 6% per day, which would give over 16 days.

I haven't changed anything.

My estimate seems to be in line with https://forums.garmin.com/sports-fitness/running-multisport/f/forerunner-945/162620/battery-life-in-smartwatch-mode/887758#887758

And then the comments that it will need some cycles, seems to be the case... Or one should keep it some hours on the charger even it's saying 100% for initial charge or something.

I'm very happy with battery life.

Charged it to 100 % sunday morning, now, after 4days and 12hours, I still have 71% left, so very pleased with that.

Bluetooth connected, no activities, stock watchface, pulse ox off, notifications on

I was happy with the battery life...hope to still be. But I was on about 50% last night, woke up and it was dead...so what happened? I’m hoping beyond hope it was a glitch and won’t happen again...anyone else experience anything like this? 

I had a Fenix 5x plus and got two weeks with smart watch and about 2 hrs of gps activity a week.  I've had the 945 for just 24 hrs now, with a 40 minute activity, and already down to 88%.  However, I've spent a lot of time fiddling with it, changing settings, adding widgets, and so on.  So it's not a good comparison yet, but still seems high.  I hope after a few charge cycles and normal usage it improves.  I don't have SPOx on.

...after 6 days in smartwatch mode (HR on, notifications on, bluetooth 24/24 connected, pulse ox off) I'm at 64%. 

Battery in 945 works in my case max 5 days and without oxy or with oxy

Some smartwatches have battery problem, after some there battery doesn't work properly.