Battery check shows battery is good, but will only work with unit plugged in.

[HPdv8tuser]

I have an (old?) HP ENVY x2 that will only work when it is plugged in.  When I run battery check it claims the battery is fine.  I assume that to run a proper battery check, it should be running on the battery at the time of checking, but if I unplug the power cord the unit behaves as if it doesn't even have a battery in it.  Are there (were there ever) replacement batteries available for these units.  I am slightly concerned that if I do not do something about this problem that someday the unit may not function at all.  Yes, I know it is over 5 yrs old, but I am not a big fan of making changes.

[Huffer]

The simple pass/fail is not reliable kind of like the check engine light in your car. And there is no problem doing the battery check while running on AC power. Yes, I assure you a replacement battery is available and likely less expensive than you fear.  

Here's the Service Manual:

Manual 

(16) Battery (3-cell, 50-WHr, 4.45-AH) 767069-006

p. 35 of the Manual has the "how to" for battery replacement. It's not the easiest thing to do. 

https://www.amazon.com/OUWEE-Compatible-HSTNN-IB6O-HSTNN-IB60-767069-005/dp/B08925PGBD/ref=sr_1_1?dc...

Post back with any more questions and please accept as solution if this is the info you needed. 

[HPdv8tuser]

So if the battery check is claiming that the battery is "OK," I am wondering if replacing the battery will likely solve the problem, or if there is something else going on.  I know it might not be possible to know for sure.  The three cells are at 4179, 4182, and 4166 mV.  Status shows 82 (not sure what that means.)  Remaining capacity is 3062 mAh, and cycle count is at 395 / 1000.  Don't know if this additional information is helpful or not.  Thank you for links to the manual and battery, I would just like to know that there is a good chance that I am looking in the right direction before attempting a battery change.

[Huffer]

Would love to see a screenshot of the advanced battery test.