Forerunner 955 losing battery quicker than normal

hi, I bought my forerunner 955 just a couple of months ago and suddenly i feel like it is losing battery way faster than when i first bought it. 

For example yesterday I went to be with watch showing 11 days of battery life, woke up and it said 8 days of battery life. i find it hard to believe that just during 8 hours of sleep it can lose 3 days worth of battery.

any suggestions of what it might be?

Thank you very much

  • download a battery widget, it will show you what percentage per hour is being used. Mine is currently showing just over 1/2%  per hour, so getting 7 days from a charge, I run sometimes with a HR strap and my shokz connected to the watch, I have a simple watch face and only record pulse ox during sleep. All of these will reduce the charge.

    I've read elsewhere, that never run down the battery and only charge to 80%, easier said than done.