About this replacement
Apple A2941 MacBook — 11.54V Li-Polymer Replacement Battery (A2797)
This is an 11.54V, 5500mAh (63.47Wh) Li-Polymer replacement battery for the Apple MacBook using OEM part number A2797. It fits the A2941 chassis, including MQKP3LL/A, MQKQ3LL/A, MQKR3LL/A, and 23 additional configurations. Install it when the original cell has degraded and the machine no longer holds a usable charge away from AC power.
- A2941 chassis compatibility: All listed A2941 models share the same battery bay dimensions, connector pinout, and BMS communication protocol. The A2797 cell fits this physical and electrical spec — no adapter or modification needed.
- Bench tested on actual hardware: We cycled this cell through charge, full load discharge, and BMS cutoff on A2941 hardware. The BMS handshake completed correctly on first connection, and charge current stepped down as expected near full capacity.
- Post-install discharge cycle: After fitting this cell, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears on the first boot after any cell swap.
Why macOS reports poor battery health immediately after fitting a new A2797 cell
The health rating in System Information pulls from EEPROM data written by the old cell — not from the new one. Until the fuel gauge IC recalibrates against the replacement chemistry, macOS has no accurate baseline and flags the battery as degraded. This is a calibration state, not a fault. Run two to three full discharge-and-charge cycles and the health reading will update to reflect actual cell capacity.
MacBook shutting down at 20–30% shown on the menu bar gauge
This happens when the fuel gauge IC's state-of-charge map no longer matches the actual voltage curve of the cell — common in the first few cycles after a swap. Under combined CPU and display load, voltage drops faster than the uncalibrated gauge predicts, triggering a low-voltage shutdown before the displayed percentage reaches zero. It is not a cell fault. Force a full discharge to hibernate, charge to 100% without interruption, and repeat once more. After two calibration cycles the gauge tracks the voltage curve accurately and the premature shutdowns stop.