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As the weather cools the battery will likely recover a little, and the Check Battery warning will go away. It's been like that for years, as long as the battery doesn't swell I'll leave it be.

Q-6

Swelling was the only reason I had to change my original one. It was still working otherwise.
 
Swelling was the only reason I had to change my original one. It was still working otherwise.
Being so old tracing a known good battery is a more down to luck than anything else these days. I guess a bridge I'll cross as and when the original battery fails. Being an older design it may be possible to rebuild the battery pack, equally not worth spending too much on such an old notebook especially the 2011 15" MBP.

Q-6
 
this MacBook was and still is a great laptop, and still can get a nice price depending on the condition
I would definitely purchase one to run Mojave and an iPad to move photos easier.
luckily the MacBook air I own since 2010 can edit and adjust hi-res photos for several hours using photoshop.
even using Mojave, but el cpaitian can run 7 house with our whirling or beachball'n
just the "service battery" is not needed, and just a meaningless suggestion.
 
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