Apple MacBook Pro 13 A1425 Replacement Battery 11.21V 6600mAh

Apple MacBook Pro 13 Retina A1425 — 11.21V Li-Polymer Replacement Battery (A1437)

This 11.21V, 6600mAh (73.99Wh) Li-Polymer battery replaces the OEM A1437 cell in the 13-inch MacBook Pro Retina A1425. It fits the 2012 and 2013 Retina models, including the Core i5 2.5, Core i5 2.6, and Core i7 3.0 variants. Swap it when the original cell no longer holds charge or macOS reports degraded battery health.

• A1425 platform fit: These 2012–2013 Retina models share the same logic board power connector, identical BMS handshake protocol, and the same 11.21V battery rail — which is why a single A1437 cell covers the full model range listed above.
• Bench tested on actual hardware: We ran this cell on an A1425 board and confirmed the BMS negotiated charge cycles correctly, the SMC accepted the cell without a fault code, and charge current stepped down cleanly at the CV phase transition near full capacity.
• Post-install calibration on the A1425: After fitting this cell, run the MacBook down to hibernate cutoff under normal use — not forced shutdown — then charge uninterrupted to 100%. This resets the SMC battery learn cycle and clears the inaccurate health warning that appears after any cell swap on this platform.

Why the A1425 reports poor battery health immediately after a cell swap

The A1425 stores charge cycle count, full-charge capacity, and health status in EEPROM on the logic board — not on the battery cell itself. When a new cell goes in, the SMC reads stale EEPROM data from the old battery and flags the health as degraded before any charge cycle runs. This is not a fault with the replacement cell. Run one full discharge-to-hibernate, then a full uninterrupted charge, and the SMC rewrites the EEPROM fields against the new cell's actual capacity data.

MacBook shuts down at 20–30% charge shown on the menu bar

This happens when the fuel gauge IC's stored capacity model no longer matches the new cell's actual voltage curve. Under full CPU and display load, the cell hits a voltage cliff earlier than the old model predicts, and the SMC triggers an emergency shutdown before the displayed percentage reaches zero. The fix is calibration, not another battery swap. Discharge fully to hibernate cutoff, charge to 100% without interruption, and repeat two to three times — after that the fuel gauge IC recalibrates its empty-cell voltage threshold to approximately 2.5V per cell under load.