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Random: Battery specs for 945LTE vs Fenix 7S

derek87
over 2 years ago

as i have noted elsewhere, one of the things that have disappointed me about the 945LTE is its battery life for smartwatch mode relative to my 935 which was spec'd with the similar 2 weeks spec. for my 935, i could hit close to 16 days with my favorite watch face, but it's more like 11 days with my 945LTE. 

in looking at the new Fenix 7 lineup, i saw that the 7S, with it's similar 1.2" screen is spec'd with 36 hours of GPS activity (very close to the 35 hours for the 945LTE) and 11 days of smartwatch mode (without solar). with these numbers and assuming the CPU is similar, it seems they just overstated the spec on the 945LTE. its my speculation now that they just used 2 weeks as a round number, but in reality, they know in testing that it's closer to 11 days. 

it makes me think that in getting  the smaller case size (2.5mm smaller), Garmin has a lower capacity battery in the 945LTE (vs 945/935) and that resulted in a drop in smartwatch battery longevity.

anyway, pure speculation, but it suggests to me that no firmware update forthcoming is going to get me close to the 14 days spec, let alone close to the battery life of my 935 for non GPS watch use. i'm glad that they improved the efficiency of GPS tracking (35 vs 24 hours really does seem to be the improvement between the 945LTE vs 935), but i wish they hadn't given me false hope that i would get something similar to my 935.

that all aside: i do enjoy my 945LTE a great deal. charging it slightly more frequently hasn't been a big deal (the shorter smart watch mode longevity has been partially offset by the more efficient battery usage for GPS activities).

  • 0 over 2 years ago in reply to nord0296

    thanks for commiserating and agreeing with my inclination to not exchange my device. the point of my message to Garmin was to raise awareness to Engineering about this problem. i still hope that happens, but i won't hold my breathe. beyond this battery life being lower than expected and a couple smaller bugs (eg, taking "double taps" to view text messages), i've been pleased with the watch.

    following up on your edit above, i find that based on their suggested setting (using their watch face with 1 hz HR and seconds showing, with bluetooth connected (no wifi or pulse), i see about 11 days. so i'm not at half of spec. just disappointed relative to my 935 which after over 4 years would easily give me 14-16 days in periods when i was injured/sick and not doing any GPS activities.

  • 0 over 2 years ago in reply to derek87
    derek87 said:
    i find that based on their suggested setting (using their watch face with 1 hz HR and seconds showing, with bluetooth connected (no wifi or pulse), i see about 11 days

    Good to know.  This is also leaving phone on overnight?  (I think you noted finding better performance by turning it off overnight in the past)

    I see ~0.5% / hr in my typical use which would get me 100% used in 6.9 days.  That generally _does_ include pulse ox when sleeping (maybe I'll turn it off and see how it changes, I acknowledge their specs do not include pulse ox).

    I also use it for 1 hr of lap swimming a week and roughly 3 hours of GPS running (maybe 1 hr of that with LTE "power save" on).

    I guess reviewing the above, my half is a little exaggerated, but like you I certainly notice it dropping faster than my old 935 as well and feel like I need to charge every few days now to feel good about it's capacity vs every week.

    Your foreshadowing of a Solar 955 w/ LTE and larger screen would be a definite buy for me but I'll guess it will not quite tick all of those boxes :)

    Honestly seeing the Epix 2 AMOLED screen makes me jealous a bit, but I then remember how frustrated I am charging every few days with my "up to 14 day" watch.

  • 0 over 2 years ago in reply to nord0296

    yes, my ~9%/day rate is leaving the phone connected, no pulse at all (i do check it manually once a day). your use of pulse-ox while sleeping would explain the differences we hae experienced.

    the Epic 2 also makes me jealous. DC Rainmaker's experience of 6 days with AOD + 6 hours of GPS activity for battery has me feeling it's not that much less than we are seeing with our 945LTEs. (6x9% + 18% =72% from what i've experienced and i wouldn't be surprised if he was using multiple GPS bands too)

    but i'm trying to be content with my watch, in spite of it missing spec. i find it hard to see myself buying a 955, even with my speculated features, only a year after buying the 945LTE. but we'll see. i tend to be easily seduced by gadgets, yet it would be nice to get 3-4 years out of this current watch. by then, there will hopefully be further advances and some "must have" features that arrive.

    as i said, i don't use LTE on my watch. now if they were able to somehow cram the capability of InReach access into a watch, i would be first in line to buy it for my backpacking adventures.

  • 0 over 2 years ago in reply to derek87

    I tend to have an early adopter problem.  I think the 945 / fenix 6 (non-LTE) may be one of the few major releases that I skipped (owned 305, 310xt, 610, 910xt, Swim, 920xt, fenix 3, 935, 945 LTE, lots of Edge models).  When fenix series aligned with 9xx series I also didn't tend to buy "both equivalent" watches (i.e. 935 and fenix 5).

    Usually I sell the last gen to almost reasonably justify the upgrade - agree that 12 months is a bit quick though.  Normally I'd aim for closer to 2 years, and as the prices keep going up it gets harder and harder to do.

  • 0 over 2 years ago

    I charged up to 100% at 2am on 25th. Today on the 29th at 6pm the 945LTE has 5% battery. My usage over these days included once a day of 18-20km running totalling 9 hours 42 minutes from 25th - 29th. So it lasted me 5 days with 117km of running. 

    I didn't use music/headphones or the maps. Screen brightness 20%, power saving mode every night, temp widget on, parkrun widget on. GPS + Glonass every sec and default watch face. No LTE used airplane mode every run and a lot of times during days. I do have a map data field every run but I didn't switch to it does that use battery even if it's not on that data screen.

    Does this seem within spec?