Forerunner 255 Series Rapid Battery Drain

Battery life for me has been quite predictable, 8 to 9 days between charges, although the 3rd charge hit a heady 10 days due to less GPS than usual.

Random and rapid drain is something that I think all Garmin users have or will experience with their devices at some stage - it seems to be an issue they never really solved, you find find threads for pretty much any device they ever made.

No advice to offer apart from its a total PITA!

Thanks. Yes, I see various past postings, many in the 245/945/645 watches. Perhaps I have been lucky over time but with the 935 prior, and a few before that, I never had this issue. I have now turned off Auto Update. Given the sporadic nature of the overnight battery drain, and not during any activity, my hypothesis is that it has to do with the watch communicating overnight through phone for updates,downloads, sync, weather, etc. Turning off BT would be the next step but that's more of an inconvenience. I also did a reset of the watch, holding Light button down until watch turns off. We'll see.

Funnily enough, the 255 is the only Garmin I have had that hasn't had random drain so far.

I had major issues with my Fenix 6 around the time of the 19.20 update when it would lose 25% a day doing nothing at all. I also had a Fenix 6x that would lose 2% an hour, so it only lasted 2 days - I documented it all in boring detail in the Fenix 6 forum in the 19.20 battery drain thread - Garmin were interested enough to enable 'secret' battery logging on my watch.

What I can tell you is that it's nothing to do with bluetooth from what I can see - the 6x was never connected to the phone at all after doing hard resets and it would still drop alarmingly. The 6 Pro with power saving had BT off 10pm to 730am overnight but battery could still randomly tank. The 6 Pro was absolutely fine during activities and the 6x drained normally then too, but used excessive amounts doing nothing....

Did you replace those watches, and if so, experience problems again with their replacements? Did the problem resolve after firmware updates? Battery hardware problems should not be random; so something is responsible for draining the battery overnight, at least for me. It would seem that Garmin could figure it out by process of elimination. For a 40-50% drain overnight, it would have to be something big like backlight, WiFi/BT comm, update processing, etc.....not something small like looking for an unconnected chest strap.

GS said:

Battery hardware problems should not be random

They do appear to be - check out the millions of 'my battery starting draining after updaing to xx.xx firmware' - most people don't have the issue, but always some people do. Why? Who knows?!

Garmin did release some special battery logging firmware for people with battery drain issues for the F6 - the fact that they released a special software purely to log battery drain suggests to me they don't know why it happens and to all intents and purposes it's random. It appears to be a software issue not hardware. Chances are the 255 shares a lot of the same code, and the random drain issue followed it over into the 255 product line is my guess. I see in the 955 forum people have similar complaints that are in the Fenix 6 foruims etc.

Changes made from version 21.00 to 21.01:

• This beta update is intended for battery drain data collection only. There are no bug fixes, improvements, or feature additions in this software. It is equal to 21.00 software with exception of the battery drain logging.'

Meant the battery hardware itself...a bad battery should be consistent/constant. Drain, on the other hand, is dependent on load, and that could be randomly high at times - firmware changes are likely culprits IMO - but we haven't had one yet on the 255, still 10.10, so maybe some other updates going on like weather, apps, etc. Or maybe something is just 'stuck'. Anyway, I'll see what Garmin has to say tomorrow. I've done a reset, and all is well for the moment.

bad battery hardware is extremely unlikely to account for all the reports we hear. Don't forgot with these sort of battery types, you can expect 300 to 500 charge cycles before it even begins to degrade much, so assuming a once a week charge, even after 4 years you are likely to have only had 200 charge cycles over a typical Forerunner or Fenix. I have a Polar V800 which is about 8 years old, that still lasts over 20 days, and I found an old Nintendo DS that must be 20 year old and that still works fine too. So bad battery hardware is quite unlikely as battery technology has been very solid for years and years.

I think what you have already said rules out a hardware battery issue - if it had a bad battery, you'd see excessive drain in activities as well when power draw is higher- but you don't. So ergo its a software caused drain. Occum's Razor being what it is....

With the FR955 there is an issue when external (ANT+, maybe also BT) sensors are connected during an activity... This causes a drain AFTER the activity (and thus in normal watch mode), In case of the 955 normal usage in watchface mode is ~0.2-0.3%/hr and with this drain it's 2+%/hr.

In my case it happens with stryd footpod, polar oh1+ and the garmin hrm run, a restart after the activity fixes the issue. Perhaps something similar is the case with the 255?

Feedback from Garmin Support: 1) likely not a battery hardware issue (would show consistent drain if so), 2) likely an issue with Connect IQ apps (Aux HR and Starbucks on watch) even when apps not being used, 3) no cases reported/opened so far of 255 battery drain. Troubleshooting steps: remove Connect IQ apps/fields and monitor for a week.