About this replacement
IBM ThinkPad i1161 / i1300 Series — 9.6V Ni-MH Replacement Battery (02K6680)
This is a 9.6V, 4500mAh Ni-MH replacement battery for the IBM ThinkPad i1161, i1300, i1171, and i1370 series notebook computers. It replaces OEM part numbers including 02K6680, 02K6870, and 02K6902. The battery slots into the standard ThinkPad battery bay and connects via the original multi-pin dock connector.
- ThinkPad i-Series compatibility: The i1161, i1300, i1171, and i1370 all share the same 9.6V battery rail, bay dimensions, and multi-pin connector pinout. One cell fits all of them without adapter or modification.
- Bench tested on actual hardware: We cycled this cell through charge and full discharge on a ThinkPad i-Series unit. The BMS handshake completed correctly, the BIOS recognised the pack, and charge current stepped down properly as the cell approached capacity.
- First-cycle calibration on ThinkPad i-Series: After installing, 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 after every cell swap on this platform.
BIOS reporting battery health as poor immediately after fitting a new cell
The ThinkPad i-Series BIOS reads health data from EEPROM values stored during previous charge cycles. A new cell arrives with no cycle history, so the BIOS flags it as degraded or unknown — not because the cell is faulty, but because the learned data doesn't match. Running one full discharge-to-hibernate followed by an uninterrupted full charge writes new cycle data to the EEPROM. After one to two full calibration cycles, the health indicator clears and the fuel gauge stabilises.
Laptop shuts down abruptly at 20–30% charge shown on the gauge
This happens when the cell voltage drops below the BIOS cutoff threshold under full CPU and display load before the gauge reaches zero. Ni-MH cells have a sharper voltage cliff than Li-ion under sustained draw, and an uncalibrated fuel gauge IC makes this worse by overestimating remaining capacity. The fix is a full calibration cycle: discharge to automatic hibernate, then charge to 100% without interruption. After two full cycles, the fuel gauge IC maps the actual voltage curve and the early shutdown stops.