255 battery drain

What means rapidly for you? disable spo2, gesture is not a problem you can set 4 seconds for the backlight, keep in mind that at the beginning the watch need to collect more data, that may be the cause.

rapidly is overnight 95% to 40%, but that was night one, seems to be getting better, will reenable gesture with 4 sec and disable spo2

Running a marathon in 1 week and trying to get a handle on thsi

After an update 2 month ago the battery dropped 20% overnight, just that time, now at 80% (from 100% 3days ago) I've run 1h30min and done 1h gym, spo2 off, wearing it all day and night, not that bad. I keep gps on auto mode for easy run, for repeats or intervals gnss works better.

i bought forerunner 255 two days ago and i have similar issue. During night it drained 13% of battery in 8 hours. After morning i turn off bluetooth, in next  8 hours it tooks 8% battery. Still high,  its looks like 3days battery life, pretty ***. Its same as my 3 years old vivoactive4. Hope that new  update will fix  it. Btw i read that some watch faces can be reason for battery drain. Will be finding problem too

I've been obsessing over battery life recently after reading through several threads on the topic in the FR255 and FR955 forums.

It seems like some differences between users can be attributed to usage of different power-consuming features like GPS-based activities and pulse-ox sensor. But it also seems like the bluetooth phone connection can unpredictably use a lot of power. Some folks see weird battery drains after they tinker with Connect IQ, and it might go away after restarting the watch.

I'm a few days into tests to see what the baseline power usage is like. I spent about 72 hours in the lowest power level I could manage with nearly everything disabled except the basic accelerometer and barometer/altimeter sensors. I did an hour long activity each day with GPS disabled so that it just did the data recording based on pedometer. My watch consumed about 3% battery per 24 hours in that period. Now, I've reenabled the wrist HR sensor to see how much it increases. But, I need to give it a few days to get some comparable readings.