How long does your 945 actually last / how often do you charge?

Marshallist said:

I'm losing 10%+ every day while doing nothing

Marshallist said:

I don't get to 6 days.

6 days worth of battery is 16.6% a day.  If you're not even making it to 6 days, you're at a minimum of 17+% a day.  Are you certain about your numbers?  When I was nursing an injury, I was using 10% a day just using Bluetooth for notifications and maybe scrolling through widgets occasionally. You have notifications turned off, but do you still have Bluetooth turned on? 

Yep, I'm certain about the numbers, I started tracking a few days ago when I took it off the charger at 100%. Currently, I'm losing a minimum of 10% a day doing nothing, plus burning a few more % during a couple hours of activities each day. When I say doing nothing, I mean I don't even scroll the widgets, I hate buzzing on my wrist so I turned off all reasons to have to interact with the watch than being able to tell time. Thus far, I'm seeing battery life very close to my Vivoactive 3 - which is what I wanted to avoid and why I made such a big jump to the 945.

"During a couple hours of activities each day" - are you kidding us?

Well, you're couple hours of activities a day is why.  Also, even if you turn off notifications,  if Bluetooth is on it's always searching for your phone. When connected to the phone, data is being processed in a background without opening Garmin Connect for things like updating weather.  Maybe you should take another week evaluating it.  You said at first you were doing nothing but steps and now you say a couple of daily activities. You also say 10% a day, but you don't make it to day 6.  The math doesn't add up.  No one will be able to assist you without all the the correct info. 

Thanks, this is helpful, I guess I find it surprising that the standby time is so iffy given how well it holds up during workouts. Maybe you're right and it's the BT, connection.

Another thing you can try if you haven't done so is fully charge the watch and then press and hold the light button for about 10-15 seconds until the watch powers off.  This will reset your watch and you won't lose any data. 

I wrote this in a Swedish Garmin Forum on Facebook after a number of discussions about battery life. I translated it to English:

What can you expect for battery time of the Forerunner 945?
The specifications are for optimal conditions so you can’t expect that for real life use, but it will still give some pointers.

The calculations are very simplified. There are some other variables to take into account, like if you navigating with maps which will use extra battery.

Specifications
Smartwatch Mode: Up to 2 weeks
GPS mode with music: Up to 10 hours
GPS mode without music: Up to 36 hours

2 weeks / 10 hours = 14 x 24 / 10 = 33.6 hours/hour (GPS with music)
2 weeks / 36 hours = 14 x 24 / 36 = 9.3 hours/hour (GPS w/o music)

1 hour training/day with music
33.6 + 23 = 56.6 h/day => 14 x 24 / 56.6 = 5.9 days

2 hour training/day with music
67.2 + 22 = 89.2 h/day => 14 x 24 / 89.2 = 3.8 days

1 hour training/day w/o music
9.3 + 23 = 32.3 h/day => 14 x 24 / 32.3 = 10.4 days

2 hour training/day w/o music
18.6 + 22 = 40.6 h/day => 14 x 24 / 40.6 = 8.3 days

My conclusion is that if you are logging activities 1 hour per day with music you will get 6 days before you need to charge under optimal conditions. In reality you will probably have to charge more often than every 6th day.
If you log activities 2 hours per day you will have to charge every 3rd to 4th day under optimal conditions.

OHR, WiFi, BT, Oxy at night 

Light&Dark = 5 days, no GPS! 0,83%/h
Infocal = testing, near 5 days, still 14% and 0,71%/h no GPS 

FR945 battery is worse than FR935. Period.