Welcome to HP Forums,
This is a great place to get support, find answers and tips,
Thank you for posting your query, I'll be more than glad to help you out ![Smiley Happy Smiley Happy]()
As I understand you are unable to install a second battery as it's not being recognized,
Don't worry as I'll be glad to help you, although, to provide an accurate solution, I'll need a few more details to dissect your concern:
Have you replaced or added batteries to your laptop in the past? or is this the first time?
If the battery has been installed as you've mentioned, did you try performing a battery calibration?Click here for details, if you haven't.
Meanwhile, I will need a screenshot of the secondary battery and how you've got it connected to the PC so that I may help you in a better way.
For instructions on replacing existing batteries, etc...Check your user manual/service guide: Click here
Let me know how that pans out,
Feel free to post your query for any other assistance as well,
It's been a pleasure interacting with you and I hope you have a good day ahead.
If you wish to show appreciation for my efforts, mark my post as Accepted Solution.
And click on the Purple Thumbs up icon at the bottom of my comment.
Regards,