Forerunner 955 Series - Recent Threads

RE: Battery issue

Bit — Tue, 08 Sep 2026 14:47:58 GMT

Maybe the built-in protection electronics in the batteries you bought is not exactly what the original Garmin batteries have, which throws off the software (just guessing)..
Focus on the marathon! That is the most important thing! Hopefully you will run much faster than your battery depletes.

Battery issue

pdurys — Tue, 25 Aug 2026 09:31:18 GMT

There are several posts here and in other subforums regarding higher than usual battery drain.

I have tried several things to fix that, but nothing works as expected.

One thing I would like to ask you - dear user community - is if someone could share yours battery stats like mentioned in my recent post here:

Troubleshooting guide for high battery drain - Garmin Connect Web - Mobile Apps & Web - Garmin Forums

I am referring to such screenshots

As you can see discharge rate between June and August looks quite the same.

Between those two days I have original battery (June) and new replaced (August)

Screenshots were taken with app from IQ Store https://apps.garmin.com/apps/923cd514-fe15-476c-855e-26846d2007ec

If by any chance someone has similar 24h span graphs from few years ago, when watch was "quite new" that would be even better.

I have run out of ideas what else to check and at this moment I incline to believe that problem is with hardware not FW.

But I will try to downgrade FW to one of previous versions and check again. For the record I have tried that already with original battery without great success.

RE: Battery issue

Brisk Walker — Tue, 08 Sep 2026 14:43:43 GMT

Thanks for your post and the snapshots.
Your watch and its battery is two years old, and you get solid seven days of battery life with seven hours of GPS activity.
My watch is now 3.5 years old, and I get a solid five days with five hours of GPS usage.
I used to think my watch's battery was poor, but after this comparison, I feel it is perfectly fine after 3.5 years of daily use.

RE: Battery issue

pdurys — Tue, 08 Sep 2026 14:27:37 GMT

I do not think anymore that it is related to battery. I am not sure right now if I have mentioned, but in the meantime "original" and "current" battery I have insert another one. But that was not able to charge more than 47% (sometime up to 51%)

Under attached label there was info ASD with size 332129 (while original has 362329), and mfg date was 250408

Maybe 3rd one would be better? Do not know. Do not want to check again. I have probably good 5h of juice to get into Starting block and run marathon, what is my goal for 3 weeks from now. If watch will "die" during marathon, then I will invest in newer model under warranty and will strictly monitor its battery.

RE: Battery issue

Bit — Tue, 08 Sep 2026 14:08:50 GMT

Wow, that is a big difference! And then I am not trying to be conservative using power; I have a CIQ watchface with seconds updates and lots of data items, have the watch connected to a phone almost all the time, often view the outside temperature from Tempe sensors, use the backlight quite a bit, and the timers and turn-by-turn navigation (both include a lot of use of the vibrate motor). Things I do less than the average user: syncing (at most once a day, and not via Garmin Connect), I don't get a lot of notifications on the watch and don't use LiveTrack.

Can you get a fresher battery? Maybe one of the big electonics suppliers like Mouser?

Activities glance on Monday shows last week's totals

Bit — Tue, 08 Sep 2026 13:58:23 GMT

When I press Start to view details, it correctly shows that there are none:

System settings: Week starts on Monday.
Not expecting an answer, just sharing because it's curious.
I know this is a user support forum (and this will also be submitted on the "share ideas" page).

RE: Battery issue

pdurys — Tue, 08 Sep 2026 13:50:37 GMT

Thanks mate. This only proves that your watch performs much better than mine.

Comparing your 24h with mine clearly proves that.

Left is overlay of that two. 27.08 is mine with "replaced battery" 07.09 is yours

RE: Forerunner 955: Massive active calorie spikes despite normal heart rate graphs (Last 6-8 weeks)

Higher4Hire — Tue, 08 Sep 2026 13:26:22 GMT

So i managed to find the fix. My HRM Pro Plus was paired with my phone besides the watch- and the spikes were happening when the band was not paired with the watch but accidentally paired with the phone (the electrodes could be wet after cleaning and in close proximity to the phone although not worn on body). I unpaired the chest strap from my phone to troubleshoot- and so far- the issue seems to have been resolved.

Forerunner 955: Massive active calorie spikes despite normal heart rate graphs (Last 6-8 weeks)

Higher4Hire — Wed, 05 Aug 2026 07:24:50 GMT

Hi everyone,

I am seeking a solution for a persistent active calorie tracking bug on my Forerunner 955 that started roughly 6–8 weeks ago. Before this, all metrics tracked perfectly.

The watch is recording massive, random active calorie spikes. However, my heart rate data does not justify these jumps, suggesting a software calculation glitch rather than a physical heart rate spike.

Calorie Widget- Shows an inflated active calorie count- with sharp, isolated vertical lines in the 12-hour timeline. Total active calories is 1167- of which 290 comes from a workout- rest all due spikes.

Heart Rate Widget- My resting heart rate is 48 bpm, and my current reading is 64 bpm. The 4-hour timeline shows typical, mild fluctuations peaking around 84 bpm—nothing high enough to trigger thousands of burnt calories.

I have seen similar reports from other users dating back over a year.

Has anyone found a workaround, or is Garmin actively

tracking this software bug?

Thanks!

RE: Battery issue

Bit — Tue, 08 Sep 2026 13:21:27 GMT

So 6 days ago I charged to 100% and today the watch was at 15%. It is charging now. Approx 14% per day, this is with on average 1 hour GPS usage per day. It is the same performance as my Forerunner 935, Fenix 6 Pro and Fenix 7 when they were a year or two old.

I was under de impression I was only getting 4 days. [facepalm:] And that totally logical because during the last half year or so, I kept the charge between 20 and 80-85% instead of charging to 100% as I did before. So I really should not complain. I am quite fed up with charging every 4 days though, so I'm about to give up on the 20-80% charging regimen.

Here are the screenprints from the app, not sure if they are useful or not:

RE: Battery issue

Orienteering runner — Tue, 08 Sep 2026 10:02:34 GMT

A replacement part is always an unknown factor, just like a long-stored original. The most reliable method is probably to directly measure the battery before installing and gluing the watch, for example, using a simple DIY battery tester.

I'm curious to see the results of your measurements using a USB tester.

RE: Battery issue

pdurys — Tue, 08 Sep 2026 08:52:52 GMT

Thanks a lot. For reference this is label from my "new battery" notice missing MFG date, and Umax ratings, but claims as much as 450 mAh capacity

It actually performs the same as original battery - which makes me consider hardware problem like ingres salty sweat inside and "change resistance" of passive elements

RE: Battery issue

Orienteering runner — Tue, 08 Sep 2026 04:39:57 GMT

What is interesting is that it is an HV type Li-ion cell and has Umax 4.45V instead of the typical 4.2V.

And it seems a step down controller is used for charging. Updated calculation 90% * 1490mWh / 3.85V = 348mAh.

Additionally, considering that not 100% of the pumped energy is available during discharge, this capacity appears to be almost identical to the original battery on your photo. And I think I can be happy with the relavely good condition of my battery 🙂

RE: Battery issue

pdurys — Mon, 07 Sep 2026 21:21:56 GMT

This is original battery i have removed from my FR955 Solar

It says 342mAh

I am not sure about your calculations, but this is what I see. You can spot mfg date 12/22/22 which is about 4y ago.

I have bought it 19/9/2023

Actually waiting for similar gizmo you have.

Current drain is about 1% per 1h without activities.

RE: Battery issue

Orienteering runner — Mon, 07 Sep 2026 20:59:06 GMT

I charged the watch from 5% to 100%. Initially, the current was 0.34A, halfway 0.2A, and towards the end 0.03A.

The transferred energy was 288mAh and 1490mWh (at 5.17V charging voltage).

Now, to translate this into Li-ion battery capacity, we'd need to know the type of charge controller inside the watch - linear or step-down. But I don,t know it.

With a linear, the capacity is below 288 mAh. With an inductive step-down controller, it will be approximately 90% * 1490mWh / 3.7V = 362mAh.

It is important to remember that a functioning Li-ion battery is able to return 90-95% of the supplied energy. In case of damaged or worn out batteries, there may be a problem that the battery will absorb much more energy than it can give off, heating up during charging.

RE: Forerunner 955: Massive active calorie spikes despite normal heart rate graphs (Last 6-8 weeks)

6932506 — Mon, 07 Sep 2026 12:46:14 GMT

Mine has the same problem over the past week or so. I'm getting record high active calories without doing any workouts. Heart rate and stress are normal.

RE: FR955 VO2 Max page bug when pressing START

Bit — Mon, 07 Sep 2026 09:14:24 GMT

The second page (when pressing start) is VO2Max for cycling (if there is a value to display), otherwise it does noting.

FR955 VO2 Max page bug when pressing START

Kpatrick1989 — Sun, 06 Sep 2026 01:50:23 GMT

On the VO2 Max detail screen, pressing START causes a page transition, but the new page is exactly the same.

There is no page indicator, no running/cycling label, and touchscreen swiping does not change pages.

No matter how many times START is pressed, pressing BACK once returns to the glance list.

This issue has existed for a long time across multiple firmware versions.

It looks like START is triggering an unnecessary or broken page transition.

RE: Battery issue

pdurys — Sun, 06 Sep 2026 06:47:53 GMT

I did factory reset. Those screenshots are actually after second battery replacement as first on could not charge more than 47 - 51% max

This somehow proves than not only watch side is monitoring charging process but also BMS inside cell.

You can see those on any Garmin battery picture.

Hence final total capacity could be also result of the battery itself. And as you will try to find on Internet battery for FR955 you will realise that such ones do not exists or are not produced "on weekly" basis.

This could answer why I see the same discharge on original battery (june) and "new" one (august). There are no currently produced FR955 / Fenix 7 cells

I will get one of those USB power / amps / voltage gizmos and post here what I see.

RE: Battery issue

Orienteering runner — Sun, 06 Sep 2026 06:36:08 GMT

Another thing I can recommend is measuring the mAh (mAh) your watch consumes while charging from 0 to 100% using a USB tester. There are plenty of cheap ones on AliExpress; I have two myself. I can perform this test myself, and you'll have a reference. While it's not as reliable as measuring the 4.2 to 3V discharge directly from the battery itself, it can still be useful.

RE: Battery issue

Orienteering runner — Sun, 06 Sep 2026 06:23:56 GMT

The seconds displayed have an impact on power consumption, but not as much as we can see in your graphs.

I replaced the battery in an FR 645 in the past.I remember two interesting things.

I noticed that when the watch wouldn't turn on (reaching 0% discharge), the battery was around 3.5V after desoldering. This could indicate either that Garmin is leaving a significant margin of charge below 0% (e.g., to keep some RTC running), or that the voltage to % scaling system is fluid and can be changed by software.

Ialso remember reading advice to perform a factory reset after replacement and perform a few 100-0-100% charge cycles, supposedly for calibration battery controller purposes.

RE: Battery issue

pdurys — Sat, 05 Sep 2026 21:40:36 GMT

Not a problem mate, and thanks for reminder.

I use stock face but with seconds.

We have asked Garmin numerous times to provide that "advertisement" face without hands, but without success.

RE: Battery issue

Orienteering runner — Sat, 05 Sep 2026 20:42:47 GMT

What watch face do you use in your tests? The watch face has high influence on power usage, but probably is not the key reason in your case.

I've noticed that with the built-in watch face, which doesn't have seconds, I get up to 8 days of battery life with six GPS workouts (some with multiband) totaling 4 hours. However, any watch face with Connect IQ, even without dynamic fields like Live HR, limits my battery life to 5-6 days.

Below is this economical watch face. Sorry for the lack of screenshot, I don't have time for that 😃

RE: Battery issue

pdurys — Thu, 03 Sep 2026 18:01:57 GMT

Thanks a lot.

I use 24h graph as this is the shortest period which can be used to compared slope of the discharge. If you could post 24h graph that would be nice.

Anyway I would say that your battery is in much better shape than mine, even after replacement. And as you have the same FW this only mean my "new" battery is not that new as should be, or there is something in the hardware which degrades over time.

Left image is yours span 3d, 1h

Right one is my from June span 3d, 18h (and this is still with original battery)

There is clear difference as my watch lost about 80% during 2 days with about 2x 1h runs yours still have 47%

RE: Battery issue

Brisk Walker — Thu, 03 Sep 2026 15:34:12 GMT

I added two screenshots after 2 and 3 days of full battery usage. See above. Firmware: 29.05.