Battery Life Decreased Dramatically

How many hours of GPS do you have in between charging cycles?  

Even with no GPS activities, 3 weeks is remarkably long.  By the same token, only 1 week with no GPS seems low.  I think the spec is 14 days max in smartwatch mode (no GPS and most battery saving settings), or up to 16 hours GPS (which would drain the battery in less than 1 day).  I've had my Instinct for 11 months and continue to get pretty close to the same battery life:  typically 1 week with 7-8 hours of GPS usage.

Some other users have noted a dramatic change in battery life, so it is possible there is something going on with some units.

Yeah ok, thx for the info. I used the GPS much more often in the summer and the battery life was really good despite that. I do some strength exercises that don't use GPS now. I barely use it at all now during the winter. I have all sensors activated and data recording every second. I have backlight set to 20% when turning my wrist after sunset and it's on for 15 sec. I turn the watch of during the night.

Don't you think it has do with the temperature outside?

I set the time with GPS though every morning.

Carl_Fredrik_Ahl said:

I set the time with GPS though every morning.

Why are you doing this? This is not necessary at all.

If you are inside when using GPS to set time, it is possible that this is causing some of your battery drain.  I imagine that the GPS might hunt for a longer period to establish a signal.  

I've had my Instinct about the same amount of time, so I'm a little worried that I might soon see a significant drop.  For me, the bigger concern would be losing half of the GPS usage time on a full charge.  I'll have to test the GPS on a full charge.

I'd expect some degradation over a year, but 50% would be too high,

Yes it really is because otherwise it will be inaccurate with about 4 seconds and I don't like that.

I'm not inside while doing this.