About this replacement
IBM ThinkPad 770 Series — 10.8V Li-ion Replacement Battery (02K6488)
This is a 10.8V, 6600mAh (71.28Wh) Li-ion replacement battery for the IBM ThinkPad 770, 770D, 770E, and 770ED notebook computers. It replaces OEM part numbers 02K6488, 02K6508, 02K7000, 02K7017, 02K7019, 12J0433, 83H6738, and ASM 83H6193. Physical dimensions are 149.40 x 90.75 x 20.80mm — verify your existing battery matches before ordering.
- ThinkPad 770 series compatibility: The 770, 770D, 770E, and 770ED share the same battery bay footprint and connector pinout. All models operate on the same 10.8V rail, so one cell revision covers the full production run of this chassis.
- Bench tested on actual hardware: We cycled this cell through full charge and controlled discharge on the ThinkPad 770 platform. The BMS communicated correctly over the SMBus interface, and charge termination triggered cleanly at full capacity without errors.
- First-install calibration on the ThinkPad 770: After fitting this battery, 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.
Why the ThinkPad 770 BIOS reports poor battery health after a cell swap
The ThinkPad 770 stores learned battery parameters — charge capacity, cycle count, and health status — in EEPROM on the battery's own circuit board. When you install a new cell, the BIOS compares incoming EEPROM data against its stored profile and flags a mismatch as degraded health. This is not a fault with the replacement cell. Running one full discharge-to-hibernate followed by an uninterrupted full charge allows the BIOS to overwrite the stale EEPROM values with real measured data from the new cell.
ThinkPad 770 shutting down at 20–30% charge shown on the gauge
This happens when the fuel gauge IC has not yet calibrated against the new cell's actual voltage curve. The old calibration data predicts a voltage floor that doesn't match the new cell, so the system triggers a shutdown well before true depletion. It is not a hardware fault. Run two full discharge-to-hibernate and full recharge cycles — after the second cycle the gauge IC recalibrates and the displayed percentage at shutdown will drop to the correct 3–5% range, with cell voltage reading approximately 10.0–10.2V at cutoff.