IBM ThinkPad 701 Ni-MH Replacement Battery 10.8V 1800mAh

IBM ThinkPad 701 Series — 10.8V Ni-MH Replacement Battery (04H619)

This is a 10.8V, 1800mAh Ni-MH replacement battery for the IBM ThinkPad 701, 701C, 701CS, and 701CX notebook computers. It replaces OEM part numbers 04H619, 04H6852, 04H6898, 04H6902, 10H4019, 25H4861, 25H4863, 44G3778, ASM 25H4862, FRU 04H6135, and FRU 04H6197. All four 701-series variants share the same battery bay format and connector, so one cell covers the full lineup.

• ThinkPad 701, 701C, 701CS, 701CX compatibility: All four models run the same 10.8V three-cell Ni-MH pack with an identical physical connector and BMS handshake. IBM standardised the battery across the 701 range so the same unit fits without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the 701 platform. The BMS communicated charge state correctly, and the pack accepted a full charge without cutoff errors or fault flags from the system board.
• Post-install discharge cycle on the ThinkPad 701: After fitting, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. The 701's BIOS uses a battery learn cycle to track capacity, and skipping this step leaves the fuel gauge reading stale data from the old cell — the health warning will keep appearing until the cycle completes.

BIOS reporting battery health as poor after fitting a new cell on the ThinkPad 701

The ThinkPad 701 BIOS stores battery health data tied to the previous cell's charge history. When a new pack is installed, that stored data doesn't match the new cell's actual state, so the BIOS flags it as degraded. This is an EEPROM data mismatch, not a fault with the replacement battery. Run one complete discharge-to-hibernate followed by a full uninterrupted charge, and the learn cycle will rewrite the BIOS health record to reflect the new cell accurately.

ThinkPad 701 shutting down at 20–30% charge shown on the fuel gauge

This happens when the fuel gauge IC hasn't been calibrated against the new cell's actual discharge curve. The gauge is still using the old cell's voltage-to-capacity mapping, so it calls 20–30% remaining when the battery is already near its true cutoff voltage. The laptop shuts down because the cell can't sustain voltage under full CPU and display load at that point — not because the battery is faulty. Complete two full discharge-to-hibernate and charge-to-100% cycles, and the fuel gauge IC will recalibrate to the new cell, resolving the early shutdown.