sounds like you might have a faulty battery.
Best app you can use to get a reading of the battery health is ‘Coconut Battery’
get a screen grab of the test screen on that app, then email them direct.
I’ve seen quite a few replacement (non-apple) batteries have issues like this, and it is nearly always a fault with the battery.
In some cases, the battery shows a full charge capacity of over 60,000 (which is physically impossible), and it powers off after a few minutes on without mains plugged in.
OWC batteries have this issue from what i’ve seen, as we sell a lot of them.