Airplane mode vs. battery saver

I would suspect they are close in battery savings (which may or may not align to what battery saver predicts) but I also assume that the Battery Saver is not very smart and is specifically looking at a few toggles to add up expected battery life.  i.e. it looks at the "Phone" toggle and adds 10 days (over it being On), but does not similarly realize that Airplane Mode turns off the same Radio and should have the same effect.

It seems like the estimates (during use and within battery saver) are all pre-programmed calculations of expected drain/life vs any real measurement of consumption.

i agree that some of the estimates seem a bit loose and inaccurate. i have decided to do some experimentation over the past week. i've tried running my watch in Airplane mode except during an activity (where i want to use a chest strap) and right after so data gets synced to Garmin Connect. after about 7 days of tracking, i would guess that turning on airplane mode saves me about 1.5-2%/day. specifically, a watch face that burns about 9%/day drops to about 7-7.5%/day battery use. i had hoped it would see a more drastic change to identify why the 945LTE is so inferior in battery consumption relative to my 935 and specs, but i still haven't found a primary culprit. 

anyway, experiment is now over. i don't want to cripple my watch's functionality to just save a few % battery consumption. (i will of course do this while backpacking). while i don't send notifications to the watch explicitly (except for phone calls so i can caller ID and determine whether to pull my phone out of my pocket), i do like to occasionally skim texts on my watch.

i'm frustrated that i can't get closer to the 6%/day i previously saw with my 935, but i guess i have to live with this reduction in battery life. as i speculated elsewhere, the Fenix 7S spec of 11 days of smart watch battery life and similar GPS hour specs seems consistent with what i've seen on the 945LTE. i can only continue to guess that even though Garmin claims it's up to 14 days, it's really closer to 11days due to smaller battery than found in the 935 and 945.

I am struggling a bit with battery life. I also run in airplane mode 23h per day, stock watch face (no seconds), no Pulse OX, all the rest being default settings. I do ~6h of run outside per week, connected to HRM Pro and battery life does not exceed 6-7 days.

In two instances, the battery dropped significantly (~20%) in a few hours. The watch was off my wrist, idling on my desk, that's the only common denominator. I have powered off the watch several time, as far as I can tell it did not make any difference.

I am coming from a Coros Vertix, and this is a bit like a cold shower. Other than that, I love the watch.

for your use, i would expect about 18% burned for activities, 8%/day for watch = 18% + 56% = 74% for 7 days.

one thing i have heard some people discovering is external straps keeping their connection long after an exercise. i saw that happen on one occasion.

also, i find my battery is very nonlinear...it sometimes drops fast, and sometimes slow, but the overall trends are what i suggested 9%/day for smartwatch (most watch faces including stock) if BT is connected (no wifi, or pulse ox for me) + 3%/hr for GPS activities with or without my HR strap.

I can confirm the external strap problem. In at least one occasion I found my 945LTE still connected to my HRM Pro after a couple of hours from a run… Battery in smart watch mode (with notifications off) is terrible.

I would not say that is is terrible, but rather mediocre. As far as I am concerned, one week-10days at best is not the end of the world. I think I am going to remove the battery % as well as the remaining days estimation, and try to live with it without thinking about it too much about it. I did not buy this watch to monitor the battery %.

I read somewhere that the 945LTE internals are basically a copy of the Venu2. Curious to know if Venu2 users experience the same battery life.

I tend to agree that terrible isn't the term I would use to describe it and feel more mislead if reality is as far off from the "up to 14 days" specification as I expected.

I am holding out a slight hope (not holding my breath) that developers will be assigned back to the watch and somehow improve various "unpolished" items, the battery life, and maybe even make the estimate useful as in it's current state it is just showing an awful guess (I have also turned that off).

The Venu2 is a tough one to compare to IMO, as the AMOLED display on that watch changes the power draw profile so dramatically that it's hard to know what we'd be looking at - merely if the claimed specs line up with what people see?  Or some display-off power usage metric?  I'm not sure...

For what it's worth, I called support today and told them about battery life. I also told them that the online user manual stated that there are  "sleep time" and "battery alert" functions in the battery saver menu (Forerunner 945 LTE - Customizing the Battery Saver Feature (garmin.com)) when on the watch there is none. All the other functions are present but these 2 ones. The support has acknowledged the difference between watch menu and user guide and has opened a case. They also told me that they are aware of battery drain issues and are working on it.

agree that's the battery life is not terrible in itself, just very disappointing and inconsistent with what was published and delivered as real world performance in both the 935 and 945LTE.

RemiM: thanks for the update. i hope they can figure out what is going on in smart watch mode. here's more speculation... the new chipset is supposed to be more efficient than the prior one, such that with a smaller battery (than the 935 and 945), the 945LTE should achieve similar battery performance as the older Forerunners. that is not the case. if they are truly working on it, there may be some glimmer of hope that the specs were somehow accurate at some point in the design/testing phase, and then something was introduced that started eating up more battery in the background.

i wish i were patient enough to use the watch for one week with a simple watch face (built in) with no seconds and HR and see how much that effects battery usage.

in the end, the week between charges is serviceable for my use case...i just find myself needing to be more mindful of how active i was during the week to determine if i need to charge up a little more quickly (6 days for example). i felt a "little more" carefree with my 935 regrading my charging cycle. i would typically charge it once a week, but i didn't have to think so much about it or monitor it as much as i do my 945LTE.

(aside: i try to not let it dip below 20% to preserve the long term battery life. as i've said many times before.  i was still getting a low burn rate on my 935 of about 6%/day using the JBlack watch face even after more than 4 years of ownership (noting i froze it at a FW13.3 a couple years in). the 945LTE isn't even close to this)

Yesterday I did 1 hour of bike indoor (with powermeter, HR band and speed sensors). The watch started with battery at 71% and finished with 68-69%. Then I changed to Battery saver mode. 24h after, the watch shutdown itself, battery 0%. 4 months without updates. This watch is a joke, Garmin!