Forerunner 255 Series Rapid Battery Drain

Hmmm, yeah... I doubt that.

First of all, never was an issue with the Forerunner 945 I had before and second I THINK I also experienced it without any connectiq fields (or at least any connectiq ant-related fields).

Easy enough to check so will do some testing back at home.

And it's true that I haven't reported it with support (there's a topic in the Forerunner 955 section of this forum though) but that's also because the other bug I reported in the end after some time consuming mails and info led to a 'oh, it seems your device is broken... please send it in for a replacement'

Went back to look at 1st incident of battery drain overnight - 1) no activity on that day preceding the overnight drain, 2) activity on the day before did not use any external sensors. WiFi was on for this incident, and off for the second incident.

So now I've turned WiFi back on, removed the Connect IQ apps (Aux HR and Starbucks), and will use RD Pod and headphones to see if I can replicate the battery drain over this next week.

Also ruled out by Garmin was any overnight updating on their side. There have been no firmware updates either since I've owned the watch.

Bottom line: it looks like for the moment that this drain is due to a faulty CIQ app, and that is what I'll be testing over this next week prior to following up with Garmin Product Supprt on the incident.

I will of course post back here if the problem persists and/or I get any additional information from Garmin.

 i observed the same on the F6 Pro...re: drain after using sensors...BT in my case. It's look like there is a rouge connection being left open.

I suspect our devices all share a common codeline, so no surprise to me the drain issue is on the 255 and the 955 too as you seem to have observed.

Ok, must admit... this might be true ;)

Did a very quick test yesterday shortly connecting my strap and noticed no drain afterwards... Starting an activity with a connectiq fields using ANT+ DID cause a drain (even if there was no strap turned on).

Currently testing something else so can't give it an actual proper test yet but might be connectiq related afterall.

That being said, this still feels like a garmin issue as the connectiq field should not be allowed to continue doing stuff on the background once you close the activity. It seems to be a problem with all ANT+ related connectiq fields so far (stryd power field, my own AuxHR field, another auxiliary heartrate field).

Also, I already have issues adding these kinds of fields anyway, adding 2 of them often causes a crash for example.

Other connectiq fields, not requiring a connection, don't seem to cause issues btw.

Interesting. The random experiences I had didn't involve actual activity use of either connect IQ app prior. Most of the time, with the CIQ apps (Starbucks and Aux HR) on the watch, I had no overnight drain issues.

Just having them installed is no issue, it's a Matter of actually using them in an activity. It's also Just the Fields with ant+ (and bt?)

I also experience  unexpected overnight battery drain (about 30% in my case)  on my Forerunner 255s Music. It has happend three times now since I have the watch, about every 8 to 9 days. 

Last time it happend I did have 2 connectiq datafields  installed, Walker and Auxiliary Heart Rate v2. The last one was only installed not used, only Walker was being used  Also the watch was disconnected from my phone and airplane mode was on. All automatic updates are disabled, both in Garmin connect and connectiq. No wifi is setup on the watch. On my phone bluetooth and wifi were disabled. For now I have removed all connectiq datafields, if it happens again I will post it here. 

Very similar to my experience, though I had BT, WiFi and Auto Update on at least the first time I experienced overnight battery drain. Common CIQ app too - Auxiliary Heart Rate v2 (a great app/data field to compare OHR to chest strap btw - thanks, FlipStone). It's only been a few days now without the CIQ apps but watch is functioning normally.

good info and now this all makes sense since i haven't had this issue with my HRM on my 955,  but i haven't been using a ConnectIQ field. on my 945LTE, i experienced the drain a couple of times, but if i recall now (it was a year ago), this happened when i was doing exactly as you suggested: using a ConnectIQ field to compare OHR vs strap. when i use strap exclusively (or OHR for that matter), no post-activity battery drain.