Sager NP862 Replacement Battery 12V 3800mAh DR36

Sager NP862 / NP8320 Series — 12V Ni-MH Replacement Battery (DR36)

This is a 12V, 3800mAh Ni-MH replacement battery for the Sager NP862, NP8320, NP6200AT, NP8600, and compatible models. It carries OEM part numbers DR36 and DR36S. Capacity is 45.6Wh — use that figure when comparing against your original cell.

• NP862 and NP8320 series compatibility: These models share the same 12V power rail, physical connector, and BMS handshake profile, which is why a single cell covers the full range. The battery management system expects the same charge termination signal across all listed models.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the NP862 platform. The BMS accepted the cell without error flags, hit full charge termination correctly, and held voltage within spec through the discharge curve.
• First-cycle calibration on Ni-MH: After installing this cell, run one full discharge until the laptop hibernates, then charge uninterrupted to 100%. Ni-MH cells require this learn cycle to reset the BIOS battery data and clear the false "poor health" warning that appears after every cell swap.

BIOS reporting battery health as poor immediately after swap

The BIOS stores capacity and health data from the previous cell in its EEPROM registers. When a new cell goes in, that stale data conflicts with what the fuel gauge IC is actually reading — the system flags it as degraded before a single cycle runs. This is not a fault with the new battery. One full discharge-to-hibernate followed by an uninterrupted full charge rewrites the BIOS battery learn data against the new cell and clears the warning.

Laptop shuts down abruptly with 20–30% charge still showing on screen

This happens when the cell voltage collapses faster than the fuel gauge IC can track under combined CPU and display load. The gauge still shows remaining capacity, but the actual cell voltage has already dropped below the BMS cutoff threshold. The fuel gauge IC needs two or three full calibration cycles on the new cell before its state-of-charge model becomes accurate. Run those cycles and the shutdown point will move back toward the correct 0–5% range.