MBP Late-2011, Battery percentage whacky

[junoreactor]

I got some whacky behavior! Just whacky!
Take a look at what happened.

Battery percentage just dropped down to 6% then hung out there for a long time.

Here's some more info on my little guy.

So I let it die completely.
Kept it off. Charged it to full. Left it off and charging +~2hrs.
You think it's calibrated now?
What's the prognosis?

 

[junoreactor]

It's whacky! Help please!

 

[BrianBaughn]

Where did you get that battery?

 

[junoreactor]

China.

 

[BrianBaughn]

It's nearly impossible to get a good third-party battery for older Mac laptops and I'd say that's the issue.