About this replacement
IBM ThinkPad A20 Series — 10.8V Li-ion Replacement Battery (02K6614)
This is a 10.8V, 6600mAh (71.28Wh) Li-ion battery for the IBM ThinkPad A20, A20M, A20p, A21, and related models. It replaces a wide range of OEM part numbers including 02K6614, 02K6616, 02K6617, 02K6618, 02K6640, 02K6746, 02K6767, 02K6769, 08K8025, 08K8031, FRU 02K6615, FRU 02K6619, and 02K6770. Check your existing battery label against that list before ordering.
- ThinkPad A20 and A21 fitment: These models share the same 10.8V three-cell-series architecture, battery connector pinout, and BMS handshake protocol — which is why a single cell covers all variants from the A20 through A21 generation.
- Bench tested on actual hardware: We cycled this cell on a ThinkPad A20 board, confirmed the BMS communicated correctly, and verified charge acceptance from empty to full without interruption or thermal fault.
- ThinkPad A20 recalibration step: After fitting this cell, run the laptop from full charge down to hibernate cutoff, then charge uninterrupted to 100%. This forces the BIOS battery learn cycle to reset against the new cell and clears the inaccurate health warning that appears after every cell swap on this platform.
Why the ThinkPad A20 BIOS reports poor battery health after a new cell install
The ThinkPad A20 stores battery health data in EEPROM on the battery pack itself. When a new cell arrives, that EEPROM carries default or mismatched values the BIOS reads as degraded capacity. The BIOS has not yet run a learn cycle against the new chemistry, so it flags the battery as poor even though the cell is fresh. One full discharge-to-hibernate followed by an uninterrupted charge to 100% rewrites the health estimate and clears the warning.
ThinkPad A20 shutting down at 20–30% charge shown on screen
This happens when the fuel gauge IC has not yet calibrated to the new cell's actual discharge curve. The gauge predicts 20–30% remaining based on old cell data, but the real cell voltage drops below the BMS cutoff threshold before that point. The laptop cuts power because the BMS sees a voltage the system can't sustain under CPU and display load, not because the gauge is correct. Run two full discharge-and-charge cycles — after the second cycle the fuel gauge IC recalibrates and the cutoff aligns with actual charge level near 3.0V per cell.