IBM ThinkPad i1400 Replacement Battery 9.6V 4500mAh 02K6530

IBM ThinkPad i1400 Series — 9.6V Ni-MH Replacement Battery (02K6530)

This is a 9.6V 4500mAh (43.2Wh) Ni-MH battery for the IBM ThinkPad i1400 and i1500 series laptops, including Model 2621-XXX variants. It replaces OEM part numbers 02K6530, 02K6630, and the ASM-prefix equivalents. Fit confirmed against the ThinkPad i Series connector and voltage rail.

• ThinkPad i1400 / i1500 compatibility: Both the i1400 and i1500 share the same 9.6V battery bay, connector pinout, and BMS handshake protocol — that is why a single cell covers the full range including the 2621-XXX model variants.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on a ThinkPad i Series unit. The BMS accepted the cell without fault codes, and charge current tapered correctly at top-of-charge as expected with Ni-MH termination.
• First-cycle conditioning on Ni-MH: After installing, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. Ni-MH cells in this ThinkPad generation require this cycle to reset the BIOS battery learn routine — skipping it leaves the fuel gauge reading 20–30% low for the life of the pack.

BIOS reporting poor battery health immediately after fitting a new cell

The ThinkPad i1400 BIOS reads health data from an EEPROM register that was written by the original factory cell. When a replacement cell arrives, that register still holds the old degraded-cell data. The BIOS has no way to distinguish a worn cell from a new one until it runs a full learn cycle. One complete discharge to hibernate cutoff followed by an uninterrupted charge to 100% forces the firmware to overwrite the stale EEPROM values. After that cycle, the health indicator clears and the reported capacity aligns with the actual 4500mAh rating.

Laptop shuts down abruptly while the gauge still shows charge remaining

This is a voltage-cliff failure caused by high simultaneous load from the CPU and display pulling the cell below the BMS cutoff threshold before the fuel gauge catches up. Ni-MH cells have a steeper voltage drop curve under load than the fuel gauge IC expects, especially in the first few cycles on a new cell. The gauge IC needs two to three calibration cycles against the new chemistry before its load-compensation model becomes accurate. Run the full discharge-to-hibernate conditioning cycle twice consecutively — after the second cycle the shutdown-under-load behaviour resolves as the gauge recalibrates to the actual cell curve.