The MacBook Pro 15-inch Retina Mid 2015 (Model A1398 – EMC 2909/2910) uses a 6-cell Li-Polymer battery rated at approximately 99.5Wh (~8460mAh) with an average lifespan of 1000 charge cycles.
If the battery shows signs of wear, such as "Service Battery" warning, quick draining, or swelling that lifts the trackpad, replacement is necessary for safety and performance.
The replacement process requires removing the bottom cover, detaching the adhesive-mounted battery pack, and thoroughly cleaning the old adhesive.
OEM-compatible batteries come with aligned screw points, pre-installed adhesive, and match the original layout without modification.
After installation, battery calibration is recommended: charge to 100%, discharge to ~10%, and recharge to full.
Typical replacement time is 1 to 1.5 hours with proper tools.