About this replacement
Acer Aspire 5550 / TravelMate 6252 — 11.1V Li-ion Replacement Battery (BTP-ASJ1)
This is an 11.1V, 4400mAh (48.84Wh) Li-ion replacement battery for the Acer Aspire 5550 and a wide range of related Acer notebook models including the TravelMate 6252, Aspire 5590, and Aspire 3628NWXMi. It cross-references over 50 OEM part numbers, including BTP-ASJ1, BT.00604.006, and GARDA32. The cell replaces the original pack when capacity fade or failure has cut your laptop's mobile use.
- Aspire/TravelMate platform fit: These Acer models share a common 11.1V three-cell serial architecture, identical connector pinout, and the same BMS communication protocol — which is why one part number covers such a broad range of machines from this era.
- Bench tested on actual hardware: We cycled this cell through full charge-discharge sequences and confirmed the BMS handshake completed correctly, charge termination triggered at the right cutoff voltage, and protection circuits tripped cleanly on simulated over-discharge.
- First-cycle calibration on Acer laptops: After installing, run one full discharge until the laptop hibernates on low battery, then charge uninterrupted to 100%. This forces the BIOS battery learn cycle to reset against the new cell and clears the inaccurate health warning that appears after every cell swap on Acer notebooks.
BIOS reporting poor battery health immediately after fitting the new cell
Acer's BIOS reads health data from EEPROM stored on the battery's BMS board. When you fit a new cell, the EEPROM contains rated factory data that doesn't match the charge history the BIOS expects to see. The system flags this mismatch as degraded or unknown health. Running one full discharge-to-hibernate followed by an uninterrupted full charge gives the BIOS enough cycle data to recalculate and clear the warning. Most Aspire 5550 units resolve the health flag within two to three calibration cycles.
Laptop shuts down abruptly while the gauge still shows 20–30% remaining
This happens when the fuel gauge IC hasn't calibrated its discharge curve against the new cell's actual chemistry. The IC is still using the old cell's voltage-to-capacity mapping, so it misjudges where the real voltage cliff sits. Under full CPU and display load, the cell hits its actual low-voltage cutoff before the OS gauge reaches 0%. Run two full discharge cycles — letting the laptop hibernate each time — and the fuel gauge IC re-maps the curve against the new cell, pushing the false shutdown point back to near zero.