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Forerunner 945 - Battery Life while running a GPX file

Former Member over 4 years ago

Hi there,

I would like to know how long the maximum battery life will be when in full GPS mode while running a GPX file on the FR 945?

in other words: Full GPS mode they say is 36 hours but how is that reduced while running a GPX file?

0 Dr Phil over 4 years ago

How long’s a piece of string?

0 Former Member over 4 years ago in reply to Dr Phil

That is not a very good answer. I am wanting to find out what the maximum battery life will be when in fill GPS mode while running a GPX file on a FR945

0 olni65 over 4 years ago

Garmin states that it's up to 36 hours with GPS, but it also depends on other settings on the watch - and as you probably are aware since asking it like that, having the map on the screen consumes even more battery than normal. There's no easy answer, why not simply test it? I remember DC Rainmaker building something to do just that

https://www.dcrainmaker.com/2019/05/random-things-did-this-weekend-94.html

0 maxkobe over 4 years ago in reply to Former Member

You'd probably have to test that out. All I can say is, that it reduces battery life significantly.

Also depends on your other settings and your sensors. Hard to tell really.

0 BeneGi over 4 years ago

There is no answer to this question.
First of all, we have to assume what exactly is a GPX file in your eyes? If it is a route, the watch will convert it into .fit at startup. If you are using a route when tracking an activity, it depends on how long the route is (how much data has to be handled in memory), if you use the map or a normal data page, the zoom level of the map (how often does it have to reload the screen), how fast you move (how often does it have to reload the screen when you use map orientation with your heading upwards), how often you leave the route...

0 badbri over 4 years ago

As others have said, it depends on your other settings. But I just tested it this past weekend and with my settings, I extrapolated it to about 20 hours of battery life. See more here:

https://forums.garmin.com/sports-fitness/running-multisport/f/forerunner-945/224651/getting-a-handle-on-battery-impacts

0 cmerrill over 4 years ago

I did a 16 hour run this past summer and wondered about this. I downloaded a data field called “Battery Up Down” that records the battery level in the .fit file. I found that navigating a GPX track while tracking my run took no, or negligiblely, more battery life than just tracking the run. So, I did the 16 hour run with every second recording, navigating a GPX track, and wrist heart rate and still had about 40% battery at the end of the day.

your mileage may vary ...

0 Former Member over 4 years ago

Just as an example I ran with a GPX and mapping the other week for 6h45 mins and had Bluetooth and everything turned on. It used about 25% of the battery life and my watch is almost 18 months old. I was pretty impressed.

0 Former Member over 4 years ago in reply to BeneGi

Thank you

0 Former Member over 4 years ago in reply to olni65

Thank you. I shall check out the link