About this replacement
Toshiba Satellite L45-SP2066 — 10.8V Li-ion Replacement Battery (PA3615U-1BRM)
This 10.8V, 4400mAh Li-ion battery replaces the original pack in the Toshiba Satellite L45-SP2066 and the broader Equium L40 series. It matches OEM part numbers PA3615U-1BRM, PA3615U-1BRS, and PABAS115. The connector and cell configuration are identical to the factory pack, so the battery seats and latches without modification.
- Satellite L45 and Equium L40 platform fit: These models share the same battery bay geometry, 10.8V three-cell-series voltage rail, and SMBus BMS handshake. One pack covers the full L45 and L40 lineup without adapters or firmware workarounds.
- Bench tested on actual hardware: We cycled this cell on an L45 chassis and confirmed the BMS completed its charge handshake, reported state-of-charge correctly to the OS fuel gauge, and held voltage under sustained CPU and display load without dropping into emergency cutoff.
- Post-install discharge cycle on the L45: After installing, run one full discharge to the hibernate cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning the L45 BIOS logs after every cell swap.
BIOS reporting poor battery health immediately after fitting a new cell
The Satellite L45 BIOS reads battery health from EEPROM data written during the charge learn cycle — not from real-time cell voltage. When a new cell goes in, the BIOS compares its stored reference against a blank or mismatched EEPROM table and flags the pack as degraded. This is a calibration gap, not a defective battery. Running one complete discharge-to-hibernate followed by an uninterrupted full charge lets the BIOS rewrite its learn table against the actual cell. After that cycle, the health flag clears.
Laptop shuts down abruptly at 20–30% shown on the gauge
This happens when the fuel gauge IC has not yet calibrated against the new cell's actual voltage curve. The gauge shows 25% remaining, but the cell voltage has already dropped below the BMS cutoff threshold under full CPU and display load — the laptop cuts power before the OS can log a low-battery event. The fix is two to three full discharge-charge cycles so the fuel gauge IC maps the new cell's voltage cliff accurately. After calibration, the gauge tracks real remaining capacity and the unexpected shutdowns stop.