How long should the M2 take to charge? Mine went from 14% to 72% in 6 hours!

semmyroundel said:

will repeat the test today, to check

I'm more curious on how you will be able to quickly deplete the battery. 

Factory reset of device:

support.garmin.com/.../

I'm doing a recharge today and I will do a discharge test tonight.  Should it be on or off all night,  if on,  inside or with view of sky? (I know if it can't see satellites it'll try to find them using more battery).

Last night,  I left it on at 72% and it was inside,  so no direct satellite view,  and in 6 hours it went down to 14%

The device controls the charge rate. Typically, LI ion devices will not charge at the maximum rate supported by the charger. Extremely fast charge is bad for battery life. Best practices are to limit charge rate to 0.5 to 0.8 of the battery capacity (C). I have no personal knowledge of what the M2 does - but that is considered best practice.

A note on charging the Mini: Plug in the power. The unit will boot into normal operating mode. Turn the unit OFF while it is charging. This will result in a "charging" screen which shows the battery icon and charge percentage. Attempting to charge indoors with the unit in normal operating mode will take a lot longer. Eventually, the unit will try a mail check, fail, and retry very, very hard. This leaves the iR modem on most of the time, which sucks power.

It is also possible that the battery gauge on a new device is not yet properly calibrated. I would not worry about the charge rate until you have been through a few discharge/charge cycles. Do not run the battery completely flat when doing the cycles.

If you do decide to return the unit, open a support ticket first. You will need an RMA anyway. In addition to factory reset, you may wish to consider cancelling the service plan.

support.garmin.com/.../

Thanks twolpert,  I've turned it off after charging initiated,  seems to be a bit better now.  I can tell you it's charging at 0.43 mahr

Just charged my M2 on a 1A brick, unit off. Took about 2.5 hours to go from 36% to fully charged.

Edvard, I charged it yesterday to 98% and left it in coat pocket, inside in the house, no tracking, brightness less than half, gps only and no connection to phone. In around 11 to 12 hours it was completely dead. I do realise that when it doesn't have view of sky it will use more battery trying to lock on to satellites.

I will repeat the test today, but with full view of the sky. Does a window (glass) impede its ability to see the sky for the purpose of this test?

GPS acquisition you can easily test by going to Navigate > GPS coordinates.

Here you can see how the Iridium satellites move:

https://iridiumwhere.com/

The connection ‘lines’ assume the inReach device is out in open grounds with free view of the sky down to horizon. 

Click on the three circles to see ca. satellite range. This way you can estimate next incoming connection and direction.

Any building, hill, valley, forest etc. towards the direction of the satellite will affect how low on the sky connection can be established. Unsure how much a window influences Iridium signals.

Horizon in this context means the calculated horizon as if you were standing in a flat desert or open ocean, not the place sky and ground meet if hilly terrain.

Rick from Hiking Emergency Beacon recently did some battery tests on the Mini 2.

https://www.youtube.com/@hikingemergencybeacon

Even if you are not sending track points, the unit WILL do an iR mail check once an hour. Indoors, it will fail. The unit will then retry - more or less forever. The iR modem consumes a lot of power - and it will be on more or less continuously once the mail check starts.

Thanks twolpert,  I will do the sky line of sight test with no activity this afternoon.  According to the hikingemaergencybeacon guy's tests on YouTube,  doing nothing in line of sight of the sky or should last 14 days 6 to 8% drop a day (I'm assuming including iR mail check you mentioned). 

Now that I've found that the charging time switched off is identical to yours,  I now need to know approx discharge times.  

No one commented on whether or not 11 to 12 hours with it in my pocket and no sight of the sky was an unrealistically short time,  perhaps you'd be so kind as to put your thoughts on this?

I don't know what's reasonable. The mail check retry is a known battery suck issue. If you think you have a battery problem, open a support ticket. None of us can really help with your specific battery life questions. Too many variables.

I will say that NONE of the 4 videos referenced in this thread addresses the scenario with no sky view. That's to be expected since it makes no real sense to leave the unit powered up indoors. The guy was testing somewhat realistic use cases.