Random: Battery specs for 945LTE vs Fenix 7S

For me, the OHR always ON is the cause of the high battery drain. When I set to OFF I have over 20-21 real days (the watch show the same), when I set OHR ON, the watch show me 14 days, but only 10 days actually. So... maybe Elevate 4 have more battery drain than the watch show (I have clear skin, no tatoos... ) or maybe there is a proccess in the background, draining battery when OHR is ON

I upgraded to the 945LTE 10 days ago and regretting it. Battery life is way less than the base model (LTE off, PulseOX off, Notifications off). It barely last 1 week with roughly 5h of GPS activities (using HRM Pro). I’m still in the return window (Amazon) and pondering a swap for a Fenix 7/Epix 2 (which will have more FW updates anyway…). But I do like the smaller size and weight though. Do you think battery life will improve in the next updates? I have notifications off but some of them are still showed by my watch. I think there is a bug and they stay on anyway. This might effect battery life too I guess. 

these are valuable insights: it seems that the battery estimates on the watch are in line with specs and inconsistent with true life left.i did ask garmin about the battery life but never got a response. i wonder if i should open another help ticket based on the suggestion that the estimates are off. they have acknowledged my request for info on why the battery saver setting options don't match the manual or what is available in other watches like the fenix.

as i've mentioned elsewhere, comparing apples to apples, the 935 has significantly better "smartwatch mode" battery use with the same watch face and settings.

the only solution i have found that would be helped by a better battery saver settings menu is to turn off bluetooth overnight when i'm sleeping (automatically) as well as turn off displaying seconds and HR at 1hz during those hours as well.

i will be very curious to hear how Fenix 7 and 7S users fare with battery life vs spec for smart watch consumption.

what really gets me is that the Epix can do 6 days of smartwatch and provide an hour of GPS use for each of those 6 days (if i understood DC rainmaker's review correctly). that's not too less i'm getting from my 945LTE.

i'm in a different set of shoes. i don't use the LTE, but i like the lightness and form factor of the FR vs Fenix series. yet the Epic 2 looks very tempting.

Been rocking my 945LTE every day for the past 6 months and was also a bit dissapointed initially with the battery life I was getting. After a lot of trial and error testing found out there are a couple of software snags that greatly impact the battery life, such as:

1. watch remaining connected to phone despite placing it in airplane mode. This used to happen to me before the last firmware upgrade. Lately though have not noticed it and battery life improved for me. My original solution for this issue was to turn airplane on and off again, reboot or do a soft reset of the watch (did 2 in all since I have it).

2. some watch faces trigger background CPU processes that eat up battery. This one is purely based on my computer engineering background as I did not have the tools to diagnose any of it but some watch faces do make the watch a bit more sluggish I noticed. There are also some bugs in the coding as even the original watch face often failed to show the airplane mode icon when this was active in the previous firmware version. Again this is mostly gone in the current FW, as far as I can tell.

3. Putting the watch in airplane mode while it is still syncing with your phone. Now this one is a big coding screw up if indeed it is a source of extra battery expenditure. I've noticed a measurable battery hit if I 'cut off' the phone-watch connection half-way, as I suspect the watch keeps trying to send out data. This instruction must get stuck in a loop in the CPU and that eats a considerrable amount of battery. The solution I found to this is to simply reboot the watch.

All this said I usually run 5-6h (standard data fields + 2 connectIQ fields) + 1-3h HIIT (standard data fields) a week, always connected with an HRM-PRO and I've been consistently getting 9-12 days of battery life, depending on any of the above issues and the amount of workout time. When not working out I have the watch in airplane mode, continuous HR measuring, no pulseOX and screen lighting to a minimum (quite sunny where I live).

Thanks for the details on your usage and experience, it is interesting to hear different settings people are using and what they see for battery life.

Jtvrm said:

I usually run 5-6h (standard data fields + 2 connectIQ fields) + 1-3h HIIT (standard data fields) a week, always connected with an HRM-PRO and I've been consistently getting 9-12 days of battery life, depending on any of the above issues and the amount of workout time. When not working out I have the watch in airplane mode, continuous HR measuring, no pulseOX and screen lighting to a minimum (quite sunny where I live).

This is interesting, although to me another example of likely not meeting the specs.  If I assume your 5-6h of running is GPS enabled and the HIIT is not, then I'd guess we'd see:

~17% battery drain from those activities (6 hrs of 35 hours GPS spec).

The 1-3 HIIT (if indoors) is effectively smartwatch mode, so I'm ignoring it.  Surely the ANT+ radio takes something as does recording the activity but I think somewhat negligible in this calculation.

To me, your idle time is even less than "Smartwatch Mode" since you have airplane mode turned on.  I think a minimum of Smartwatch mode is a phone connection for notifications (or it is just a watch, not a smartwatch).  Really I think it should be OHR + Phone.

If we pretend Airplane mode is smartwatch mode, we'd expect 14 days * 0.83 (subtracted 17% for your activities) and we would see 11.62 days (which is still the high end of what you note seeing, and you've turned off BLE).

Another data point... using "Battery Saver" just now I modified the settings to only toggle my Phone to "Turn Off" while leaving everything else as "Don't Change".  I feel like this should tell us what Garmin's firmware thinks the Phone connection weighs in battery drain.  In my case I had 83% battery when I did this, my estimate was 12 days (we know it is more like 6-7 at this percentage).  The estimate turning on Battery Saver with this setting changed to 15 days.  So in effect Garmin thinks your Airplane mode usage should bring typical usage from "up to 14 days" to "up to 19 days" vs your 9-12.

Ironically if I ignore battery saver and toggle airplane mode I notice my estimated 12 days does not change but power saver still seems to imply I'd gain 3 days from enabling it (which should be untrue as I've already disabled my radios).  If I instead disable Bluetooth via the "Phone" item in Connectivity (rather than Airplane mode) my estimate does change from 12 days to 15 days.

In pulling this together I realized their spec is "up to 14 days" and I'm hoping they aren't playing a ridiculous game where typical settings is always going to be 7-8 days but turning everything off gets you close to 14.  Given the estimate shown on the device I feel like this isn't the case, but... <shrug>.

-edit to add-

I just realized they _do_ specify their assumptions for the 2 week specification: https://support.garmin.com/en-US/?faq=oU83zXuPHdAMHymFLDl8N9

I think I generally agree with this table as being a valid "smartwatch mode" and it's probably close to my usage (I have no idea how many notifications or interactions I see a day, but guess it's less than their table).  Yet we're missing 14 days by almost half...  They don't note OHR settings in the table but I have to assume "Default" (24 hr monitoring).

i found this on Garmin's website:

https://support.garmin.com/en-US/?faq=oU83zXuPHdAMHymFLDl8N9

as nord0296 suggests, there are two issues at play here: 1. specs, 2. what the watch provides as an estimator.

- i think that if they really set up the battery saver properly which would allow things to "auto-shutdown" overnight it could indeed see closer to the 14 hour spec, and maybe even close to the 16 hour estimate.

- to me, smartwatch mode can't mean disabling BT and going into airplane because that removes what i would call Garmin's barebones smartwatch features: notifications/reading texts/weather widget updates.

for my setup: using a variety of fairly "miserly" Connect IQ" watch faces and Garmin's own which all have 1hz seconds and 1hz HR, 24 hr OHR, no PulseOx, notifications only on phone calls (but i read texts occasionally), i am getting 8-9% per day use in Smartwatch mode. it's closer to 10-12 for the first day or so (showing the battery meter isn't accurate) but the rate slows down and averages 8-9% until my typical charging at around 30% left. (i usually charge up to 95% or so). on my 935, with the same sort of smartwatch features active, i used around 6% per day. again, i speculate that the battery in the 935 might be slightly larger (as would be true for the 945)... i also speculate that somehow the new chipset is supposed to be more efficient theoretically, but its not doing that in real life. (interesting to note the 35 vs 36 hr GPS spec for the 945LTE vs 945). i find the 35 hr estimate is a very good estimate of real life performance.

ps. does anyone remember which was the "default" watch face that shipped with the watch? maybe a digital with 1hz seconds but not showing HR?

crazy follow-up. i decided to send an extensive email to product support. the response i got was that i needed to send my watch in. no thank you... with everyone's reports here, there is 0% chance that there is anything faulty with my watch. i do not think i'd want to play roulette with Garmin and end up with a unit with bad buttons (my first watch had bad buttons).

i've told the support agent that everyone here has the same less than stellar battery life and i would assume engineering can easily confirm something is amiss by running tests on their in house models (although i realized, one thing they would need to do is wear the watch because if not, i assume OHR would shut it self off if a watch is left sitting on the shelf connected to a phone with built in watch face and 1hz HR and seconds shown)

Bummer.  I reported a slew of issues that all seemed software related shortly after receiving my watch (basically ordered at launch).

They acknowledged many of the concerns (generally after requesting photos or videos... of things that were easy to reproduce).  But also wanted me to exchange my watch for one of the issues noted.  I was fairly certain it was a software issue and would still be present on a replacement, but went ahead with it anyway at the time.

Of course the replacement had the same problem, and then further had trouble transferring my LTE subscription properly (I think I had to cancel and re-setup LTE vs transfer an active subscription).

I can't recall what the issue was now, but believe they may have addressed it in the semi-lone firmware update back in... October?

I too would not exchange my device now unless I was fairly sure an issue I was seeing was most likely unique to my hardware.