Out of warranty, Apple charges $199 for replacement.
iFixIt.com has the battery itself for $89.99. The battery that iFixIt sells says the design capacity is 5260 mAh.
Since 5260*.73=3839.8, I've lost about 27% battery capacity in 231 charges.
The Apple support site states I can still use the MacBook while connected to the correct power adapter. In June 2015 (according to MacRumors), Apple changed their battery replacement policy for AppleCare customers. AppleCare costs $249 or $349 depending on the MacBook model. This extends warranty coverage to 3 years from the original purchase date (for the MacBook, not the AppleCare).
Some underwriting that I did not read yet:
- Once a person gets their battery replaced under the AppleCare warranty, does that extend the battery's warranty an additional 3 years?
- Or is it only 1 year for the battery?
- Do you pay another fee to warranty the battery?