Extreme battery drain since update to 13.00 (e80dcb4)

I'm experiencing the same on my forerunner 245. Recently updated to v13 and overnight went to 5% from a charge the evening before. No GPS or any activity logging. Would love to rollback, haven't seen any benefit to v13 and with this amount of drain I won't be able to use for long activities planned soon.

I gave up and bought a Venu 3, even though it was difficult considering how Garmin handles this issue. Where is Garmin's response to this issue? 

The final response from Garmin was "We quote up to 6 hours of battery life with this combination of features" after indicating they think I can get almost 5 hours from monitoring an activity on my account. They have made no explanation of v13 software and the increased drain on the original and replacement watches. Their argument to me is also flawed since (1) 5 hours vs up to 6 hours is 16% lower, (2) it previously would last up to 10 hours and (3) it implies that 10 mins would be acceptable as it's "up to 6 hours". VERY disappointed with their response.

Power drain issues after updates have been a commonly reported problem for a long time. Not the same issue but right after I bought my 245 an automatic update killed the performance of the optical HR sensor. I returned the watch, got another and have only done one update in the last 2 years, I needed that update and it was done just before the warranty lapsed.

I don't know if Garmin asked you to do it but historically there have been a few posts where a factory reset after an update solved the power drain issue. I've no clue if it would help but it looks like push has come to shove, so why not.

The negative is you would loose any calibration / user settings and the activities. The activities are easy enough to back up and restore via a USB cable to a computer. I think the settings are in a file that can be saved/restored but I won't stake my life on that, it's been a while since I tried to sort that out.

I'm here because I was checking updates to see if any improvement had been made to treadmill calibration. Mine does not seem to calibrate as well as it did before the last update but there quite a few variables in play and one of them is me (stride length).

Based on comments such as I've been reading, I will probably just avoid updating from 11.6 for now. The decision is reinforced by Garmin not letting a person return to an older version of the software should something go South resulting from the update

I really do love the use of my 245, but updates and management decisions that prohibit returning to the prior version leave something to be desired..

Thank you so much for taking your time to write such a detailed and thoughtful reply. I am absolutely with you on loving the 245 but just being very frustrated with this specific issue and Garmins response. Your suggested idea seems brilliantly simple and I can't believe I haven't thought of it! Thank you again and wishing you a very happy new year. 

Happy New Year to you too. Just for information's sake, on 11.6 and a 2 year old battery, 2 hours and 12 minutes of outdoor activity today used 26% of my battery. 

Hard reset, deleting all data off watch and phone, charging to 100%, turning off everything, nothing has worked. Watch went from 100% last night to 40% this morning and I was only sleeping. Rang up customer support and they offered to replace it and upgrade it to the 255. Customer support is A++ maybe they know its an issue?

there seems to be a bug where after you end an activity, it somehow stays active in background.(but doesnt show)   like unable to auto kill the activity after saving.  

I find if you restart watch after ending and saving an activity, the drain stops. ( or restart watch after a multi workout session )

while annoying to restart watch after a workout session, it is the only workaround for me.

Yesterday I had the same kind of issue: battery went to 1% extremely fast, I charged it to 100%, then after I lost maybe 1% per minute! I tried to restart the watch and it seems this solved the issue. I had my 245 since one year and never had this issue before... If the issue come back I will try the workaround from Mike Y "restart watch after ending and saving an activity", thanks! I had installed the Battery Gauge Widget to trace the battery drain and I found the widget useful.

Good to know and glad you logged it, if there's a bug in the firmware it improves the chance of Garmin finding and correcting it. What version of firmware are you on?