ACTEBIS Targa TN549 Replacement Battery 10.8V 4000mAh

ACTEBIS Targa TN549 — 10.8V Ni-MH Replacement Battery (DR35)

This is a 10.8V, 4000mAh Ni-MH replacement battery for the ACTEBIS Targa TN549 notebook. It replaces OEM part numbers DR35, DR35AA, and DR35S. The battery restores mobile operation to the TN549 when the original cells have degraded past usable capacity.

• Targa TN549 fitment: The TN549 uses a specific connector pinout and BMS handshake tied to the DR35 part family. All three OEM part numbers — DR35, DR35AA, and DR35S — share the same voltage rail and physical housing, so this cell covers all variants without modification.
• Bench tested on actual hardware: We ran this battery through charge and discharge cycles on the TN549 platform. The BMS handshake completed correctly, charge acceptance was confirmed across the full 10.8V range, and the cell held voltage under combined CPU and display load without dropout.
• First-cycle conditioning on the TN549: 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.

Why the TN549 BIOS reports poor battery health after a cell swap

The TN549 BIOS reads health data from EEPROM stored on the old cell. When a new cell is fitted, that data is gone and the BIOS flags the battery as unknown or poor. This is not a fault with the replacement cell — it is a data mismatch. Running one full discharge-to-hibernate followed by an uninterrupted full charge gives the BIOS enough cycle data to recalibrate. After two to three full cycles, the health status returns to normal.

TN549 shutting down at 20–30% charge shown on screen

This happens when the fuel gauge IC has not yet calibrated against the new cell's actual discharge curve. The gauge is still using the old cell's curve, so it reads 20–30% while the cell voltage has already dropped below the load threshold. Under full CPU plus display draw, the cell cannot sustain voltage at that point and the laptop cuts out hard. The fix is to complete two full discharge-to-hibernate and full charge cycles — after that, the fuel gauge IC maps the correct curve and the shutdowns stop.