235 battery life - post your experience!

While having my FR235 received 7 days ago I did charge it up three times until last saturday :(

Ever since this last charge 86 hours have passed (3.5 days). In that time I did about 80mins of GPS activity. Everything except smart notification is turned on, however I try not to keep the GC app open all the time to save connection power (don't know if that matters at all when phone is locked?)

Battery is now down to 68%, having maybe 3% gained through PC syncing.

Depending on how much I pick up on GPS activities, it should be good till the end of the week. I have no idea why battery life suddenly seemed to get much better, maybe it was kind of self calibrating?

I installed the "battery gauge" widget, this gives a 7 day graph of battery %.

I'm under the impression that battery life is improving after a few charge cycles. The first week I barely managed 2-3 days, but now I can make it to almost 5 days without charging. This is with everything on (except backlight), and around 2 hours of GPS activity per cycle, no firmware updates.

Also, the decrease in percentage is not always linear, the lower the percentage gets, the longer it lasts (i.e. it goes pretty quick from 100%-90%, but takes much longer from 30%-20%).

Anyone else have the same experiences or am I imagining things?

I'm under the impression that battery life is improving after a few charge cycles. The first week I barely managed 2-3 days, but now I can make it to almost 5 days without charging. This is with everything on (except backlight), and around 2 hours of GPS activity per cycle, no firmware updates.

Also, the decrease in percentage is not always linear, the lower the percentage gets, the longer it lasts (i.e. it goes pretty quick from 100%-90%, but takes much longer from 30%-20%).

Anyone else have the same experiences or am I imagining things?

Maybe because you're going on a GPS run right after charging to 100%? :D

Counting 4.5 days now, down to 40%, including about 130mins of GPS runs. Todays 50min run cost me around 10% battery life just for the run.

Although the battery life was really bad for the first full charge cycle, where I only got about one day out of it. I've been getting 2 full days on each charge with 24/7 HR, BT, notifications, activity tracking, and 1-1.5 hours of running per day.

This is okay for now, but I'd really like it to be much closer to the stats they listed prior to release.

i have charged using their garmin usb charger yesterday from 10% to 100% in 2-3 hours but i left the watch plugged in for additional hour. after that

backlight off
wrist turn backlight off
bt on (most of the time to connect to my phone)
hr 24/7 on
notification on
no running since

i checked this morning and it went down to 86% so within last 20 hours, it used 14%. it seems a lot.

i have another 235 coming in UPS and will be here by friday. I will first charge it fully using USB charger and not to play with all the settings and other stuff yet and see how all turns out. I have a feeling that i might have messed up the very first charge when i got the 235. i only charged it using PC for an hour or 1.5 hr and as soon as i saw it reached 100%, i unplugged.

i have just upgraded the software to 3.2 and the sensor hub after i plugged to my PC using garmin express.

https://forums.garmin.com/showthread.php?337137-FR235-Firmware-updates-v3-20-and-v2-30-quot-Sensor-Hub-quot-(2015-12-09)

I hope the 24/7 HRM battery will be improved by this fix.

If you want to know how to drain nearly half your battery in a single 33 minute run, continue reading:


1. I'm recovering from injury so I set my alerts to keep my heart rate between 131 and 141 to keep the run easy.
2. I'm night running so I have the light set to stay on permanently during the run.
3. I have my lap alerts set to 1/4" miles increments.
4. GPS+GLONASS

Final result: the battery life went from 96% to 53% in that single run. I was surprised but at the same time understood why.


Because the sensor on this watch is "spikey", I found myself undercompensating and overcompensating every time it alerted me that my bpm was too high or too low. It was cold (low 50's), windy (~15mph) and hilly (~250 feet climb during a 1 mile portion of my route). So these conditions make it kinda hard to keep the effort steady. The end result was constant buzzing and chiming. Solution: install and use latest firmware and set the heart rate window to 130 min. and 142 max. for a larger window with the intention of keeping it as close to 140 as possible and turn off the backlight. My average heart rate for the entire run was 140bpm so mission accomplished, but the battery suffered!

While having my FR235 received 7 days ago I did charge it up three times until last saturday :(

Ever since this last charge 86 hours have passed (3.5 days). In that time I did about 80mins of GPS activity. Everything except smart notification is turned on, however I try not to keep the GC app open all the time to save connection power (don't know if that matters at all when phone is locked?)

Battery is now down to 68%, having maybe 3% gained through PC syncing.

Depending on how much I pick up on GPS activities, it should be good till the end of the week. I have no idea why battery life suddenly seemed to get much better, maybe it was kind of self calibrating?

I installed the "battery gauge" widget, this gives a 7 day graph of battery %.

Interesting... in 2.5 days with 80mins of GPS my watch lost about 30% of battery.

Now, two days later (hence 4.5 days in total) I'm down to 9%. Meaning in those two days with about 90mins of GPS usage I lost about 60% of charge, double as much in almost half the time, and this includes one day with the new 3.20 firmware... DUH! :confused:

EDIT: corrected the days, I was counting wrong :rolleyes:

Lithium ion battery technology hasn't changed.

Charge as needed