235 battery life - post your experience!

235 vs 230 battery performance

Just wondering.. If there is no difference between forerunner 230 and 235 with the exception of the inbuilt HR sensor in the latter, is it possible that their battery performance is different when the HRM in 235 is off? If not, I would personally go with 235 when comparing these two watches. It is nice to have the option for monitoring HR without having to wear an HRM strap. Your opinions?)

Some math to use to guide our expectations, using Garmin's own claims:

The number of days the watch should last with 24/7 HR on and X hours of GPS activity is approximately (1-X/11)*9.

So after 4 hours of activity in 5.7 days the watch should require a charge. And after 6 hours of activity in 4.1 days it'll need to be charged. So the ballpark time between changes should be between 4-6 days for 4-6 hours of activity.

Some math to use to guide our expectations, using Garmin's own claims:

The number of days the watch should last with 24/7 HR on and X hours of GPS activity is approximately (1-X/11)*9.

So after 4 hours of activity in 5.7 days the watch should require a charge. And after 6 hours of activity in 4.1 days it'll need to be charged. So the ballpark time between changes should be between 4-6 days for 4-6 hours of activity.

Your second example is pretty much what my usage is and with the 225 I do have to charge it about once a week. So assuming either a larger battery or more efficient hardware/firmware in the 235 I think it would be reasonable that the higher draw of 24/7 HR you should be able to see similar battery life.

A good rule of thumb is to also subtract an hour so from claimed battery time. I've had pretty much every GPS a watch there has been and found that's pretty accurate.

If I get 8 hours out of this watch I'll be very happy. I can't imagine ever running anything over 4 hours and any epic bike rides I do are covered by my edge 520.

If I wanted over 10 hour battery capacity I'd be looking at the fenix3 or maybe the Suunto Amit 3.

163

While I agree that early reports indicate Garmin has overstated battery life, you are reading the specs incorrectly. Garmin states a FR235 battery life of "11 hours training, 9 days watch + activity tracking + notifications + heart rate". Note the comma versus the plus signs. You get 11 hours in training mode OR 9 days with activity tracking and no training. Not both, as you imply. That said, there is a big difference between 5-6 hours of training several people seem to be getting and the 11 advertised.

i think that is what I understand.

11 hours training
OR
9 days watch + activity tracking + notification + 24/7 heart rate

11 hours training is a big jump from the 225. When I had the 225, it would only last ~6-ish hours with GPS on. I tried to track my movement using GPS when I was in disneyland last time and my watch died around 5pm and i was there since 11am.

Some math to use to guide our expectations, using Garmin's own claims:

The number of days the watch should last with 24/7 HR on and X hours of GPS activity is approximately (1-X/11)*9.

So after 4 hours of activity in 5.7 days the watch should require a charge. And after 6 hours of activity in 4.1 days it'll need to be charged. So the ballpark time between changes should be between 4-6 days for 4-6 hours of activity.

did you mean the 4-6 hours of activity (as running and using GPS) in total in 4-6 days?

did you mean the 4-6 hours of activity (as running and using GPS) in total in 4-6 days?

Yep. Actually ~4 hours GPS activity will leave ~6 days of battery for the activity tracker. And ~6 hours GPS activity will leave ~4 days of battery for the activity tracker. Using Garmin's numbers.

The math is a bit approximate and will depend on other things. But as a rule-of-thumb: 4-6 hours GPS activity leaves 4-6 days for activity tracking (inc. 24/7 HRM monitoring).

Has anyone read Ray's in-depth review?? He didn't get very good batter life on his.

He states, "FR235 Battery Life: It’s bad. Really bad. It’s about 2-2.5 days for me, using the optical HR sensor on its usual continuous mode (24×7). It’s supposed to be 9-11 days. Garmin says they’re aware of the issues and are working on it, with hopes to issue a firmware update in a few weeks. I’m sorta realistic though that something will have to give here – such as reduced sampling rates. Perhaps I’ll be proven wrong, but it’s a pretty big jump to increase battery life 4x over what’s there today without any negative impacts."

Now that most people have had a few days to play with their FR235, how is the battery life doing for them??

Has anyone read Ray's in-depth review?? He didn't get very good batter life on his.

He states, "FR235 Battery Life: It’s bad. Really bad. It’s about 2-2.5 days for me, using the optical HR sensor on its usual continuous mode (24×7). It’s supposed to be 9-11 days. Garmin says they’re aware of the issues and are working on it, with hopes to issue a firmware update in a few weeks. I’m sorta realistic though that something will have to give here – such as reduced sampling rates. Perhaps I’ll be proven wrong, but it’s a pretty big jump to increase battery life 4x over what’s there today without any negative impacts."

Now that most people have had a few days to play with their FR235, how is the battery life doing for them??

It seems from reading through the comments on the other threads here that most (but not all) are having a similar experience to Ray. I.e. pretty crap battery life.

It remains to be seen if it can totally be fixed with a software update. Fingers crossed!

Battery Best Pratices

Hello everybody. Besides the issues or ways of use our Garmins Fenix 2, do you know what are the best pratices about the charging process, to allow us to extend the battery life? For instance: what's the minimum % we need to start the charging? Do we need to get closer the 0%? More: do we need to perform always a full charge (or is it better to stop in a specifc % of charge)?

Thanks a lot
Trajano (Brazil)