Battery Drains While Shutdown

use a "shutdown" command to ensure that all systems, including "standby" and "hibernate" are off. 

Have you tried to check if that is happening?  FWIW l have been experimenting with (what I expected would be) Hibernate with the charger disconnected and then using the Power button to turn it off and finding that it is somehow coming back to life in the middle of the night,

then not even appearing to be back to Sleep.  In the morning the UI was what I expected, i.e., I had to use the Power button to try a Resume but this file proved that something else entirely was going on when it was supposed to be "powered off"

C:\Windows\System32\SleepStudy\user-not-present-trace*.etl

In fact, in the middle of that trace Message Analyzer shows a record containing Critical Battery Trigger met but then it goes on doing some kind of intensive processing (almost like an unlimited loop).  Also, somehow according to the related file in the  ScreenOn  subdirectory my screen was turned on hours before I actually "Resumed" it using the Power On button.  It's nonsense.  My guess for the best way of controlling it would be to boot in another OS which does know how to Hibernate properly.

So, it doesn't look like a bad battery to me but to unreliable, incompatible software that is supposed to be managing it but doing a really bad job of that.

FYI

Robert Aldwinckle

Thanks for your comments and suggestions.  I haven't checked to see if the "shutdown" command is actually doing what it is supposed to, and I haven't really run any more tests.  

At this point it has become a time/money issue; it no longer makes economic sense for me to continue to put diagnostic effort into this computer.  I will keep my charger handy and when the time comes I will purchase something other than a Surface. 

I understand that hardware and software fail, I understand that issues come up that are difficult to solve.  To me, the biggest issue is Microsoft's complete refusal to address this problem beyond a few cursory steps when they have so many complaints about the same issues.  (Issues - 1.  Battery Drain; 2.  Their refusal to acknowledge).

Thank you for your comments.  As I mentioned in another post, I'm at a point where it is no longer practical for me to continue to put so much time into diagnostics and testing.  I'll keep my charger handy, and when the time comes to replace this computer I'll look for something other than a Surface.  

The issue for me is not the age of the battery or the hardware/software problems - I understand that this happens - but rather, it is the complete and transparent lack of any kind of acknowledgement on the part of Microsoft.  Once users have uploaded their powercfg results, they are dropped from conversations and ignored.  

It would make me feel a whole lot better if Microsoft were to say something like, "We recognize this is a widespread issue and our engineers are investigating it." It would be even better if they were to create their own forum or web site where this issue could be reported so they could collect some real data.  

Instead, as I have said before, it is not an unreasonable belief that Microsoft has concluded that this problem may be too expensive for them to address, and they are taking the chance that we'll just go away. 

I'm sure they have forecast that if we all abandon the Surface product and it goes away, the damage to Microsoft will only be that that part of the company will have to lay off their employees.  The number of Surface users who will transition to Apple will be negligible, and Microsoft will continue to sell software.  So why bother?  

I believe that the only way to get MS to acknowledge this problem is to make it public - to send copies of these threads and the hundreds of complaints to magazines that review technology, to the BBB, and to Consumer Reports.  Post on Facebook.  This country responds best to bad publicity.  This little forum, while often helpful, is too contained to really make a difference.

I am currently looking at the Surface Pro 6.  Before I purchase, I want to know how much it will cost to replace a battery in an $1800 unit.  I think the answer to the question may keep me from going down that road.

I have not seen any info on this. My SP 5th Generation (2017) box stated the battery was replaceable. That statement was on boxes for all previous SP boxes.

Microsoft has never, ever replaced just a battery. They have only exchanged for a complete refurb device. While the device is "current" they've been charging around $450 for this. And for the older devices (most likely to have battery needs) I've seen $600 and then they get marked discontinued and there is no way at all to do anything. (Like the SP3, which went from $450 to $600 last spring . I wrote https://digitalmediaphile.com/index.php/2018/04/09/pricing-for-out-of-warranty-surface-exchanges/ in April. If you check https://support.microsoft.com/en-us/help/4023527/surface-how-to-get-service-for-surface and compare the prices to my blog post, you can see how some items are now completely unavailable. 

(I'd be curious if the SP6 boxes still show the statement about replacing batteries). 

SP3 owners, inflicted with batterygate, tried to get the $200 battery replacements https://www.reddit.com/r/IAmA/comments/26m9cu/we_are_panos_panay_and_the_surface_team_at/chsei5u/ 

TL;DR see today's Computer World post https://www.computerworld.com/article/3316937/microsoft-windows/it-s-time-for-microsoft-to-fix-the-surface-pro-4-mess-by-offering-no-hassle-refurb-sp5s.html