Montana 700i keeps turning off

It may vary in different locations due to different laws. I am not sure what it is outside of the US as this is a US forum. You would need to contact your local/regional Garmin Support to find out for your area. 

Yes. I have had two 700i. Both same problem. It is NOT the cradle as Garmin-Leslie write. It is the unit itself. It turn itself off even powered by USB or 12V in the mount cradle. Mine is mounted inside my boat. Dry and stable. I have tried with and without external antenna. I have turned off all other electrical instruments around. Also WiFi. I have tried to put it in a cabin with no satellite coverage. Powered by USB and no cradle. Same problem. 

Very annoying since my inreach tracks are getting splitter in pieces. And I always have to turn it on when I see it is off. 

What is strange  - before I replaced my first unit I had it on, powered by USB in my home inside with no satellite signals. There it was on for several days without turning off? That is why I suspected some interference in my boat, but after lot of testing I don't think so. It is a problem with the unit.

I definitely do NOT have this issue. I am running the Garmin 750i on the factory cradle for the past 3 days at 8 hours a day. It has been on the dash bearing the full sun and has had several hi temp warnings but NO shutdowns. Mine is working great - and hardwired into my vehicle’s 12v port.

not sure what is going on with your units but mine is fine.

8 hrs a day. No problem. Try several days in a row. Mine is supposed to be on all the time week after week onboard my boat. That is the problem. I just crossed the Barenz Sea. A trip of 4 days. My Montana shut down 4 times during the trip. This is a replacement unit. Same problem. I have no temperature issue. 20 degrees celsius in my pilot house.

After a lot of testing with two brand new 700i units I think I have found the source for this problem. As far as I know this happens only with the 700i (InReach version) and not the 700. Both units always turned off randomly when they had satellites. My first one was turned on in my home without coverage before I turned it in and got a new one. Then it was on for more than one week.... I suspected some radiation in my boat. When I received my second unit I turned off all other electrical stuff around it. I moved it to different places in my pilothouse. It always randomly turned off. Then I moved it ino one of my cabins so that it has no coverage. Now it has been on for a week.

It has nothing to do with cradle, powersupply or external antenna. The problem is most likely something between the GPS signals and the Iridium signals. I heard on a Youtube review of this unit that the GPS+GLONASS was not an option since Garmin had problems with this together with the InReach functionality (antenna). My thinking then is that this is still a problem. Mixing GPS and InReach in one antenna (very close together). I have tried both GPS and GPS+GALILEO. Same problem with both. 

I suspect Garmin knows about this and therefore no solution since it probably require a total HW change?

Great debug, thank you.

btw: hope just the SHUTDOWN prevention (thats all we need) wont require hardware change.

Well, finally my 700i decided ...Why no me too. I have not  had the switch off issue, I decided no updating as every new update was worst than before, in some kind of  brain storm or stupidity , I read on the forum that the thing looks like better since 15.10 so I decided to update my 700i unit to this .... and .....drums please..... my [moderated] unit start to switch off randomly , so I was so worried about not being accepted in the elite group of 700i , but Garmin make me a favour and I reach it, I´m in the last problem group of my unit. Thank you Garmin I thought I wouldn't make it. I´ve update from 14.8 to 15.1 and the unit start to switch off , I always have the unit connected to  microusb port as a way of energy , I used an magnetic plug to avoid problems on the port due to vibrations , but it was updated to 15.10 and on my first trip I suffered the issue three or four times a day.

May be Garmin´s still thinking there is no way in satellital guidance if you don´t have a Garmin device....

Sorry , I´m so frustrated, The thing is, if Garmin solve the lots of [moderated] of the unit, it is a very good deviced, when it is working I love it but then suddenly Garmin decided reward you with a new problem , what such a toxic relationship , ha,ha,ha..

Thank you for you patience, mates

Moderated for language: Putting asterisks in the text does not excuse the language.

Most current firmware version is 15.20.

yep.. but no mention about sudden restarts in the changelog.

My Montana offered me this update yesterday... just after booting from unwanted shutdown while driving :D Normally I use Garmin Express, but this time I tapped yes and updated firmware using built-in updater.