Sager NP6856 NH58RCQ 14.4V Replacement Battery 2200mAh

Sager NP6856(NH58RCQ) / NP6876(NH70RCQ) — 14.4V Li-ion Replacement Battery (NH50BAT-4)

This is a 14.4V 2200mAh (31.68Wh) Li-ion battery for the Sager NP6856(NH58RCQ) notebook. It also fits the G70R, NP6876(NH70RCQ), and NP7853(NH58EDQ), among other models sharing the same battery bay. OEM part numbers covered: 6-87-NH50S-41C00 and NH50BAT-4.

• NH50/NH58/NH70 platform compatibility: These models share the same 14.4V four-cell battery architecture, connector pinout, and BMS handshake protocol. One cell fits all because the power rail and communication lines are identical across the NH5x and NH7x chassis generations.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a compatible NH58RCQ chassis. The BMS negotiated correctly, the BIOS recognised the battery without a firmware error, and the fuel gauge IC began tracking state-of-charge within two cycles.
• Post-install calibration on NH-series laptops: After fitting this cell, run the laptop down to hibernate-cutoff on battery alone — no AC connected — then charge uninterrupted to 100%. This triggers the BIOS battery learn cycle, clears the "poor health" warning that appears after every cell swap, and gives the fuel gauge IC a clean reference point against the new cell's actual capacity.

BIOS reporting poor battery health immediately after fitting the NH50BAT-4

The NH-series BIOS reads health data from the battery's EEPROM, which stores cycle count and state-of-health values written by the previous cell. When a new cell arrives, the EEPROM data does not match the fresh chemistry, so the BIOS flags it as degraded before a single cycle has run. This is not a fault with the replacement cell. Run one full discharge to hibernate-cutoff, then charge to 100% without interruption. After that cycle, the BIOS resets its learned capacity figure and the health warning clears.

Laptop shuts off hard at 20–25% battery shown on screen

This is a voltage cliff — at high CPU and display load, the cell voltage drops faster than the fuel gauge IC can track, and the BMS cuts power before the displayed percentage reaches zero. It is most visible on NH58/NH70 chassis when running sustained workloads because these platforms draw harder under GPU and CPU combined load. The fix is a full calibration cycle: discharge the laptop to automatic hibernate under real workload, not idle, then charge to 100% in one session. After two such cycles, the fuel gauge IC recalibrates its discharge curve against the new cell and the premature shutdowns stop.