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Garmin 935 Battery

I have a 5+ year old Garmin 935. Wear it every day, one workout a day basically, probably 1/3 with GPS, for that time.  I've noticed in the last few months a massive drop in battery life.  It's now lasting only a few days max. Today went from a 100% charge this morning to 53% charge after 5-6 hours and I expect it will be in the teens within a couple of days.  

Is this normal degradation in battery life? or is it something wrong (and I haven't changed any settings on it for like a year)? 

Top Replies

  • Is this normal degradation in battery life?

    A li-ion battery should survive about 500 charge cycles without a significant decrease in performance, perhaps more than that in some circumstances…

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  • keep us posted on your attempts to remedy the situation. finger crossed that a reset would solve the problem. as long as all your data is in Garmin Connect, going for a full factory reset wouldn't cost you anything but a little time. if not, then the FW downgrade is more work, but still a viable solution assuming you can find the firmware files somewhere.

  • More important (imo), which gpsfirmware do you have?

    Mine is on 2.70 and has a huge batteryuse when using gps. If I remember correct, pre 2.50 I hadn't.

    Unfortunately, gps firmware cannot be downgraded.

  • 4%... but then it started climbing and :30 later the battery is up to 20%.  

    No, this could be a battery issue where the battery under stress (due to high demand by the watch activity) delivers a lower voltage than when your watch is more or less idle.

    Mine has the same but less extreme. 

  • it is entirely possible it's the battery although that suggests a defective battery that didn't make it through too many cycles.

    if i recall, at least to me, Garmin previously had a service to swap out an out of warranty watch for a refurbished one. i can't recall the exact amount (it must be somewhere here in the Forums), but to me, it seemed like a very fair price (i believe it was something like $60 USD but i could be wrong)...but i would pursue the course i suggested above before making such leaps.

  • just found my own post...should have waited to complete my post. at least a year ago, it was $99 to get a replacement watch out of warranty. IMHO, that's not bad at all if needed.

  • Here in the Netherlands it is way more expensive to swap your device for a refurbished one (garmin support in the Netherlands is really lousy.)

    But I just see how long my watch last. Not that keen to spend any money on garmin as I’m looking at Coros as a possible next watch (or Polar if they finally add navigation to their watches. Yes their grid has navigation, but only with a paid komoot subscribtion)

  • did you ever figure out a solution to your battery issues? lately, i've been wanting to upgrade my FW but am scared to do so given some of the reported problems of excessive battery drain.

  • I didn’t. I have honestly stopped wearing it right now. Partly because I’m on an injury hiatus, and partly because it was just annoying always worrying and and unsure of the battery. It was losing about 1% and hour but also at times it would unexpected drop to 4%, then climb back to 20%, then drop to 5%, then go back to 25%. Just got fed up with it so it’s in the drawer for now. 

  • sorry to hear about your injury and frustration. i hope you recover soon and can either fix your 935 with a hard reset or maybe get Garmin to send you a refurbished for $99 (at least that's what is available in the US).

    crazy as it sounds, as much as i'm disappointed that the 945LTE isn't the 955 i was waiting for (hoping for a 1.3" screen and same form factor at 935), i'm somewhat tempted to pick up a 945LTE for Maps and the slightly smaller form factor. (i don't have any real need for LTE feature)