Battery display after last update

Since a recent software update my 235 battery percentage is unreliable. Yesterday I was on 72%, ran 5 miles, it dropped to 22%. Half an hour later it was back up to 50%. Put it on charge when I got home and it dropped to 46%, unplugged and it dropped to 45. Then it shot up to 90%, but by morning it was down to 80%. My friend has a 735 and it’s doing the same thing.

  • Since a recent software update

    Which version? There hasn't been an update for the 235 since August 2020. 

    • There was an update on 19th November 2023. It wanted to install as I stood on the start line of a race so I can’t mistake the date. I deferred until after the race. There was another about a week later, and another about a fortnight ago, or thereabouts. System - About  says version 8.20 (8dffc71) My friend with the 735 is on 9.20 and having the same problems. It had never had a problem previously.  I’ve had to click to accept the update each time.
  • Which version is on your watch? Menu > Settings > System > About.

  • As stated above - 8.20 (8dffc71)

  • As stated above

    Just checking, because that was released on August 4th, 2020 - Garmin: Forerunner 235 Updates & Downloads

    Strange that you recently received this update.

    You can try some of the suggestions here: Troubleshooting guide for high battery drain. Look at the section "The battery gauge is decalibrated."

  • I have no idea how long it's been on 8.20, or what the updates last November contained, whether I was on an earlier version or not, but it was the release a couple of weeks ago (ish) that seemed to cause the battery to drain, or the status to be wrong. One time I went out with about 75%, did 5 miles, got home with it beeping at me and the centre square turned black on 2%, but before I plugged it in it went back up to about 65%. I don't think the issue started after the November releases because I'm sure I would have noticed?

    I'll try the High Battery Drain solution tomorrow, as I'm about to go to bed (21:45 over here). But the last few times I've had it on charge it hasn't reached 100%, 90% was the max, after about five hours. 

  • I do have a watch screen installed on it, but that's been there for a few years, plus a couple of widgets (is that what they're called), but ditto for those. But my friend hasn't installed anything on his 735, it's still as it came.

    I've just opened Garmin Connect on my lap top and it is saying there are new updates available - 35.00 Time Zone Maps and Personal Records. Maybe these are the types of updates that have been applied, not a main system upgrade?

  • Sorry, I've now tried this five times, but still the same issues. This morning I went out on 89%, ran for five miles, finished on 18%, within a couple of hours I was back up to 60% (without charging it), but now I'm back down to 38% and have used it just as a watch all day, no tracking. My friend with the 735 still has the same issue despite following these instructions.

    I've found another friend with a 235 whose watch has hit the same issues. It was working fine last November (19th, she was at the same race as me) but it stopped working about a fortnight afterwards following an update. Even when left on charge all day it won't go above 95%, and can deplete to zero in a few minutes and turn off when used to track a run (though not always). When connected back to power it is immediately almost at full charge.

    Another friend with a 235 doesn't have any problems, but he hasn't applied any updates since he got it as he doesn't have a pc.