Garmin Forerunner 955 Battery Fail – Why does it drain?
Garmin Forerunner 955 Battery Fail – Why does it drain?Return to the Garmin Forerunner 955 Solar Review
There is something weird happening with the battery drain on the Garmin Forerunner 955.
Mine seems broadly fine when recording workouts but it’s at other times when the battery seems to drain far more quickly than I’d expect. An example is this morning when I clicked on my Morning Report, looked away for whatever reason and then looked back at a blank screen. The battery had gone down from at least 10% to zero overnight.
Garmin Battery Life Claims
Let’s start by looking at exactly what Garmin claims the 955 can deliver with the battery. As you can see, it has shown the settings and general usage conditions required to mee the performance levels.
Garmin doesn’t seem to be trying to hide anything here like other companies sometimes do. Do you want maximum accuracy plus music?…that’s 8.5 hours. It’s still good. I’m sure almost all of us are happy to take a battery hit if we choose a higher accuracy mode.
- UltraTrac Mode without Music Battery Life Up to 80 hours/110 hours with solar
- Smartwatch mode: Up to 15 days/20 days with solar
- GPS Only Mode with Music Battery Life Up to 10.5 hours
- GPS-only mode without music: Up to 42 hours/49 hours with solar
- All Systems GPS Mode with Music Battery Life Up to 10 hours
- All Systems GPS Mode without Music Battery Life Up to 31 hours
- All-Systems GNSS mode plus Multi-Band with music: Up to 8.5 hours
- All Systems GNSS mode plus Multi-Band without music: Up to 20 hours/22 hours with solar
- All + Multi-Band GPS Mode without Music Battery Life Up to 20 hours
- All + Multi-Band GPS Mode with Music Battery Life Up to 8.5 hours
Solar charging, assuming all-day wear with 3 hours per day outside in 50,000 lux conditions
Even better, Garmin is super-clear about some additional factors that will affect battery consumption during workouts.
| Number of Interactions per Hour | 10 |
| Minutes of Interaction Post-Activity | 1 |
| Number of Gestures per Hour | 8 |
| Display Brightness & Timeout | Default Settings |
| Assumed Temperature Range for Battery Life Specifications | 10C – 40C |
As we will see shortly, it’s smartwatch usage and the following claims that might be one of the sources of problems that people have with the battery outside of exercise.
|
Smartwatch Mode Usage Assumptions |
|
| Notifications per Day | 90 |
| Number of Interactions per Day | 160 |
| Device-Generated Alerts per Day (Move or Goal Alerts) | 2 |
| Hours per Day Outside of Bluetooth Range of Phone | 1 |
| Display Brightness & Timeout | Default Settings |
| Watch Face | Default |
| Number of Gestures per Day | 200 |
| Pulse Ox Mode | Disabled by Default |
| Number of Minutes of Music Streaming | 0 |
| Number of Timed Activities | 0 |
| Smartwatch Mode Battery Life | Up to 15 days |
Garmin Forerunner 955 Battery Performance Test
This is an excerpt from my Garmin 955 Accuracy & Performance Tests that I posted a few weeks back.
These battery consumptions all use Multi band and optical HR and broadly seemed to validate the 20-hour battery life claimed by Garmin.
- 6%/hour gives 16.67 hours capacity – on a very sunny day!
- 4.8%/hour gives 20.83 hours capacity – on a sunny evening with the sun low in the sky
- 3.6%/hour gives 27.71 hours capacity on a long sunny bike ride
- 6%/hour gives 16.67 hours capacity under fairly dense tree cover
- 3.69%/hour gives 27 hours capacity on a late evening run with no sun.
I have the solar model and so battery results varied according to sunlight conditions.
Reported Battery Consumption Outside of Workouts
The problems seem to be occurring when outside of workouts. Some of the battery drain figures reported on the Garmin forums are surprising. Try these
If I boot up the 955 and don’t turn on any activities, the battery life show normal behavior, it drain 3-4% per day, but after finish some activity (like running), the battery will drain 1-2% per hour! @9858591
I haven’t been super impressed by the battery life. I’ve seen what others are seeing. 3-4% loss each night. @Yoder
I’ve had mine for less than four days and charged to 100% twice. In that time, I’ve logged 90 minutes of activities. It looses 50%+ each day. @Simulacre
Got the watch 4 days ago and charged it yesterday when it hit 60% went to be on 92% and woke up today on 62% something not right @Paulb
I have also noticed unexpected battery drain, where I am losing about 10% per day, even on the days when I’m not using GPS @PaulSmith1984
So we are talking 13-14% over 2 days which translates to 14-15 days. so that’s not super bad. @Derek87
So What Is Causing This
I’ve been playing with this for a couple of days and there seems to be a bug either with the WiFi connection or the Bluetooth connection when completing a workout and uploading it. However, it’s not just that, there also seem to be some watchfaces that might cause issues and the inadvertent use of backlight, gestures or SpO2 contributes too.
Here’s What I Did
- I use GPS-only during workouts, I don’t need more accuracy than that.
- I used the old Crystal watchface from my 935. That hadn’t been released on the 955, I just copied it across. So now I’ve switched to the highly similar Crystal Tesla watchface. Other owners suggest using stock Garmin watchfaces but even then some are suspected of using excess battery eg Titanium.
- Remove any watchface complications that show Bluetooth or phone connectivity
- Restart the watch after uploading your workout. This seems to clear either the WiFi/Bluetooth connection. (Press and hold the top-left button)
- System>Backlight>During Sleep>Timeout 8 seconds
- System>Backlight>General Use>Timeout 8 seconds & Brightness 5%
- System>Backlight>During Workout>Gesture>After Sunset
- System>Touch>General Use>Off
- System>Data Recording>HRV>Off
- System>Data Recording>Smart>On
- Wrist Heart Rate>Broadcast>Off
- Wrist Heart Rate>Status>Auto
- Wrist Heart Rate>Pulse Oximeter>On Demand
- Disabled Bluetooth and Wifi and used cable upload via Garmin Express
You can obviously save more battery than that. eg by disabling wrist HR entirely, turning off the backlight, disabling SpO2, disabling notification, unpairing from Connect on your smartphone, and so on. But you want something usable on your wrist.
Another thing to try is completely discharging the battery and then completely recharging it. Then repeating. That might reset and calibrate the battery charge monitoring software.
Firmware v10.10
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I went from 100% to 71% in 4.5 days. Then I went from 71% to 19% overnight. I also noticed that sometimes the back light follows the do not disturb rules and sometimes not. On this night it did not. I’m not sure if this would account for such a big drop or not.
yes the backlight will eat battery, more so with a higher %age brightness
My money is on Bluetooth. Historically Bluetooth is a weak point for Garmin and more so with the Fenix 7 / Epix 2 generation. There are crashes and hang conditions that seem tied to bluetooth that are not entirely resolved. I think the bluetooth stack for the current hardware platform is not fully debugged.
I would try airplane mode and see if it magically makes the battery life amazing. That would tend to implicate bluetooth. It should make a small difference but not a huge one.
ConnectIQ watch faces definitely burn dramatically more battery than the stock ones. Anything ConnectIQ is always suspect and to be minimized in my book. The new ConnectIQ runtime with extra new features I’m sure only makes it more complex and likely to have new bugs.
I think the version number 10.10 is kind of interesting. I bet anything it will eventually align to the fenix 7 / Epix 2 firmware number which is currently at 8.37 and apparently in a stabilizing phase with a new major feature rollout coming in a couple of months. DCRainmaker reported that the new beta program is also associated with a new development strategy of stabilizing periods and feature periods.
I think what may be going on is strategically two branches of development that will debug issues separately and then be merged.
That’s really strange, I am about to post a review in a few days expressing the opposite. I am consistently getting 10 to 11 days and at 60% brightness, which is incredibly bright for a Garman watch and typically cuts the battery life in half at least. I’m recording at least one workout a day, minimal GPS usage, and full tilt watch usage all around. I use it for Weather and widget checking and all the notifications, which are a lot throughout the day.
Found this the hard way. Got my 955 on Wednesday, configured everything and went for short a run, had about 70% battery. That night went for an extended weekend, decided not to take the cable with me because it was at freaking 70% an hour before right? Friday morning went for a hour run, lunch, then in the afternoon when I looked it was at around 40%! Fiddled a bit with settings, made sure Pulse Ox was off, etc, but when I went to bed had less than 10% left. This is Apple Watch battery performance (aka bad). Slept with it anyway, got no sleep data that night. Sunday morning went for a run with my wife Zepp watch… 🙁
Meanwhile charged it to 99% on Sunday afternoon back home, went for a hour run, was 95% after (seems reasonable with no accurate measurements), went to bed with about 80%, woke up with about 60%… Today just read this, will try changing more settings, but didn’t buy this watch to have to babysit the battery…
Yep, for the first time in nearly 2 decades I had a Garmin watch die on me! Fortunately I had taken a tiny usb-c/garmin adapter (lighter pocket) and could recharge during the weekend.
The trick for now is to reboot after each activity, then the smartwatch is as expected, i.e. 15 days.
Thanks will keep restarting after workout, till they figure this out. Meanwhile put Wi-Fi off, let’s see if it helps too.
yes ctrl-alt-delete works as well 😉
2022 – this is a bit pathetic isn’t it!
actually, people knock the apple watch but Apple controls power consumption really well so you know where you stand and you know you have to adapt your charging routine and you know you can rely on a super quick charge if you need it. perhaps Garmin owners might now take a pause for thought.
Fortunately the 955 seems to charge pretty quickly, but didn’t think it was back to daily charging with a Garmin.
This seems like a huge launch bug and hopefully they will rectify it quickly.
I remain concerned that the complexity of the feature set that Garmin is shipping combined with the very old-school embedded architecture without guard rails like memory protection and processes (let alone process scheduling and preemptive multitasking) is an albatross around their neck.
It seems like each generation is harder for them to stabilize.
The restart seems to have worked, went to sleep with 88%, woke up with 86%, have 85% right now (with about 40m at 50% solar charging).
GarminOS runs CIQ apps in a little vm. They control scheduling, the compiler, the memory. So not quite old-school embedding. All faceplates and activities are apps.
It’s almost certainly a bug regarding ANT+ (and perhaps bluetooth) connectivity, when doing an activity which has an ANT+ sensor connected (such as a stryd or HR strap) this seems to trigger the drain. Before drain in ‘watch mode’ is ~0.2%/hr, after that ~2%/hr.
I now simply restart after having done such an activity and this solves it for me it seems… I have not yet seen it happen with activities without any sensors attached.
Of course this should be fixed by garmin, but at least knowing the issue (and workaround) makes it bearable at the moment.
With 3 or 4 runs a week (60 to 90′) for a little less than 3 weeks, plus two short bike-commute, with at least two ant+ sensors connected, multiband GPS, i dont reproduce the draining battery pattern.
I’m on a reg955 @10,10 and 20% luminosity.
Hmmm, that’s strange… most have been able to reproduce. Do you happen to have wifi disabled/not set up by any chance? (As another user in this thread has the feeling that wifi might cause it somehow)
Even though for me it simply only happens in the situations I described above
There could be a backlight issue with the Gesture feature on the 955. Every run I’ve done thus far has seen normal arms swings set off the backlight, meaning the watch is basically lit for the entire run. I’ve fed details to Garmin and they indicate there is a firmware update coming regarding the Gesture feature (without confirming it’s related to my specific issue).
ty for that. I had a suspicion over gesture and/or backlight but i have the backlight so low that i don’t always notice its behaviour unless I’m specifically looking for it coming on. Gesture seems to come on when i want it to very nicely. hopefully they don’t change that aspect of it too much
If you can afford this than you can afford a fenix 7…every other watch they have makes sense except for the 9xx series. Spend a couple more dollars and add quacamole.
Looks like I’m pretty lucky with mine, and pleasantly surprised. I did a 5:15 trail run yesterday, and the battery dropped 3.8%/hr – that’s with GPS Only and course navigation. That’s a very good result, and means I’d be fully confident of not needing to charge on a 100k + event. I need to test similar with music, and that will def change things!!
that’s about what you get with multi-band. I’ve noticed but not quantified that gps-only doesn’t always seem to save battery.
OK, good to know. The GPS conditions were just about perfect, so thought I’d just drop to a basic level to give the best battery conditions I could. I’d also forgotten my phone, so Bluetooth was disconnected the whole way, no notifications etc.
Based on several tests with settings I think the problem is Wi-Fi. With Wi-Fi off I don’t get battery drain, even with several runs with ant sensors and no restart after. My suspicion is that if you have Wi-Fi configured but then the watch drops out of range, it keeps trying to connect like mad in the background and run your battery to the ground.
Interesting, will give it a try to see if I can reproduce
Sorry, probably not Wi-Fi after all. Everything seemed normal but then I lost 20% battery during the night, no idea why. Right now during the day seems normal, only about 2% so far.
Haha, no worries… Indeed found out the same, immediate drain with wifi off after an ANT+ enabled activity.
Had the same problem with 255s. Down from 100% to 5% in 20hrs. The problem is with synchronizing your garmin. In Connect app check your garmin device and synchronize, wait with BT connection till the end, finally theres an update on your Garmin, you need to confirm it.
I did this 3 days ago and so far no problem with battery life. Hope it helps.
Do you run with a stryd connected? I found my battery drains at 2.6-2.7% per hour after a workout with the stryd footpod and the power field added to your data screen. Removing the power field and not taking the stryd out leaves the battery draining at the standard 0.2% per hour. Currently talking with garmin support about it. Disabling absolutely everything (full power saving, even hr turned off) while the power is draining at ~2.7% does not affect the drain at all, it stays constant. Def something garmin needs to fix asap.
there were some similar comments in the Garmin forums about stryd but then other people reported similar problems with other sensors and that led the thinking back to Bluetooth (even though stryd was probably linked by ant+)
anyway: in my case, when I am testing I don’t pair either stryd or an HRM nor (usually) add a data field, so that i can test the accuracy of the inbuilt sensors and it was happening then as well after I finished testing.
There was exactly the same problem with vivoactive3 like year ago. I basically learned to turn it off/on after every workout. I guess sometimes gps stayed on after workout for no reason.
yep
different gps chip this time tho.