About this replacement
Apple MacBook Pro 17" MA611B/A — 10.8V Li-Polymer Replacement Battery (A1189)
This is a 10.8V, 6600mAh (71.28Wh) Li-Polymer battery for the Apple MacBook Pro 17". It fits the MA611B/A, MA611J/A, MA611LL/A, MA092CH/A, and 22 additional MacBook Pro 17" variants that use the A1189 cell. Install it when the original no longer holds a charge under normal use.
- A1189 platform compatibility: All listed MacBook Pro 17" models share the same 10.8V three-cell architecture, A1189 connector pinout, and SMBus BMS handshake. Any unit in this range accepts this cell without hardware modification.
- Bench tested on actual hardware: We ran this cell through charge-discharge cycles on a MacBook Pro 17" logic board. The SMBus communication initialised correctly, the BMS accepted the charge profile, and macOS Battery Status reported full capacity without throwing an unknown-cell error.
- Post-install calibration on the MacBook Pro 17": After fitting, run the battery down to hibernate cutoff under normal load — screen on, applications running — then charge uninterrupted to 100%. This resets the SMBus fuel gauge learn cycle and clears the inaccurate health flag macOS shows after every cell swap.
Why macOS shows "Replace Now" immediately after fitting a new A1189 cell
The MacBook Pro 17" stores battery health data in EEPROM on the SMBus controller. When a new cell goes in, the controller reads cycle count and state-of-health figures from its own memory — not from the new cell. Until the fuel gauge IC recalibrates against the new chemistry, macOS treats the battery as degraded. This is not a fault with the replacement cell. Run one full discharge-to-hibernate cycle followed by a full uninterrupted charge, and the health status will update to reflect actual cell capacity.
MacBook Pro 17" shutting down at 20–30% charge shown on the menu bar
This happens when the fuel gauge IC has not yet mapped the new cell's voltage curve. The displayed percentage is based on the old cell's discharge profile, so the system hits the real low-voltage cutoff while the gauge still reads 20–30%. Under full CPU and display load, the cell voltage drops faster than the stale model predicts, triggering an immediate shutdown. Charge to 100%, then run a controlled full discharge to hibernate without interruption — after two to three such cycles the gauge recalibrates and the shutdowns stop. At that point the resting voltage at "0%" should sit at approximately 10.0–10.2V before hibernate kicks in.