Battery advice

I posted before about a battery problem with my NP550P5C laptop, but can't find that thread now. Anyway, today the battery no longer keeps the computer running at all. It was working fine, and then I unplugged the computer from the power adapter to move it to another room, and the computer shut down immediately. Not an orderly shutdown.

With the battery installed, the computer will not power up at all unless the adapter is also plugged in. However, Windows shows the battery as 79%, available, plugged in, charging. But the 79% never changes, and the battery light never changes from amber to green. Battery Info View shows fairly normal numbers, with the wear level at 75%. Shortly after powering up, I do get the strangely worded battery warning that the battery "isn't the longest".

I've tried cleaning all the contacts on the battery and the computer, with no effect. Of course I'm hoping it's just a bad battery, but it's curious that it failed suddenly. I had operated on battery alone for several minutes earlier in the day, with no problem, so it's just strange that all of a sudden it delivers no power at all.

I've seen proposed fixes on Youtube ranging from freezing the battery overnight to uninstalling all of the entries under Battery in the Device Manager. But aside from ordering a replacement battery, is there anything else I need to consider or try? Has anyone here been down this road and can offer any comfort on this (that it's not a computer problem)?

Edit: And I guess while I'm at it I should ask where the CMOS battery is on this computer. NP550P5C-T01US

 

Probability is one, if not more, of the Lithium cells has folded. This will make it so the battery never fully charges and under any kind of amp draw the voltage will drop so low you will get a hard shutdown.

 

Yes, I'm hoping that's all it is. I think I'm going to go ahead and order a "compatible" battery, and see what happens.

If the new one works, then that settles the issue.