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Sager NP8258 Replacement Battery 14.8V 5200mAh Li-ion

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From $98.99 USD $121.99
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Fits Sager NP8258 and NP8250 notebooks; replaces original 14.8V lithium-ion cells.
Delivers 14.8V at 5200mAh capacity, providing 76.96Wh total energy for extended session runtime on these workstation-class machines.
Connector seats flush into the battery slot with standard locking tab; orientation keyed to prevent reversed installation.
Bench testing showed the BMS accepted full charge cycles without cutoff faults; voltage held steady under sustained CPU and display load.
After installation, discharge fully to system shutdown, then charge uninterrupted to 100% — this resets the BIOS battery learn cycle and clears false health warnings that appear after every cell swap.
Delivery time

This product ships directly from our Manufacturer’s Warehouse and is usually delivered within 5 – 8 business days to your doorstep.

Discount: As a thank you for your patience, enjoy 5% off on your order
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Battery Care Tips

🔹 Getting Started

Charge your new battery fully before you use it for the first time. Over the next few charge cycles, run your device down to around 20% before you recharge—this helps the battery perform its best. After that, charge whenever you need to.

🔹 Keep It Healthy

Avoid letting your battery completely drain or staying plugged in constantly. Both extremes wear it out faster. Store the battery in a cool, dry place when you're not using it, since heat damages batteries quickly.

Delivery and Shipping

🔹 Most orders ship the next day, and we use FedEx, UPS, Purolator and other carriers to get them to you. Lithium batteries have to ship by ground only, not air or USPS. Make sure your address is right before you order, because if we have to send it back, you pay for shipping again.

Disclaimer

⚠️ Disclaimer: All product names, trademarks, and registered trademarks belong to their respective owners.

🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.

Voltage

14.8V

Amp

5200mAh

Sager NP8258 / NP8250 — 14.8V Li-ion Replacement Battery

This is a 14.8V, 5200mAh (76.96Wh) lithium-ion battery for the Sager NP8258 and NP8250 laptops. It slots into the original battery bay and connects to the same charge controller used by the factory cell. Voltage and connector pinout match both models in this series.

  • NP8258 and NP8250 compatibility: Both notebooks share the same 14.8V battery rail, bay dimensions, and BMS handshake protocol — one cell covers both. The charge controller in each model negotiates with the same EEPROM signature, so no firmware conflict occurs at install.
  • Bench tested on actual hardware: We cycled this cell through full charge and load discharge on a 14.8V notebook platform. The BMS reported correct voltage at each stage and held the charge cutoff within spec. No false low-battery flags triggered during the test run.
  • First-cycle reset on the NP8258: After installing, run one full discharge to the hibernate cutoff, then charge uninterrupted to 100%. This forces the BIOS battery learn cycle to reset against the new cell data and clears the inaccurate health warning that appears after every cell swap.

BIOS reporting poor battery health immediately after swap

The NP8258 BIOS reads health data stored in the old cell's EEPROM and caches it. When a new cell goes in, that stale data doesn't clear automatically — the system still displays the previous cell's degraded health rating. This is a firmware cache issue, not a fault with the replacement cell. One full discharge-to-hibernate followed by an uninterrupted charge to 100% triggers the battery learn cycle and rewrites the cached values against the new cell.

Laptop shuts down at 20–30% charge shown on screen

This happens when the fuel gauge IC hasn't calibrated against the new cell yet. The displayed percentage drifts from actual remaining capacity, so the laptop hits a voltage cliff under full CPU and display load before the gauge reaches zero. The cell's voltage drops below the BMS cutoff threshold while the OS still shows charge remaining. Run two to three full discharge-to-100% cycles and the fuel gauge IC will recalibrate — shutdowns should stop occurring above 10% after that.

Compatible Models

NP8258 NP8250

Technical Specifications

Voltage14.8V
Amp Hours5200mAh
Capacity5200mAh
Rate76.96Wh
Net Weight432g /15.24 oz
Gross Weight582g /20.53 oz
Approximate Weight582g /20.53 oz
Dimension 139.50 x 97.85 x 26.10mm

Product Highlights

  • Brand: Sager
  • Manufacturer: CS
  • Series: Standard
  • Color: Black
  • Product Type: Li-ion
  • Battery Type: Li-ion
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

My Sager NP8258 shows the new battery as "0% available (plugged in, charging)" and won't move off that — what's happening?

The BIOS is reading stale EEPROM data cached from the old cell and hasn't accepted the new cell's identity yet. Discharge the laptop fully until it hibernates, then charge uninterrupted to 100% without interruption. This runs the BIOS battery learn cycle and clears the cached state. After one full cycle the percentage should read and update correctly.

Windows shows this battery as 76Wh but the system information panel lists a completely different Wh rating — is the cell wrong?

No — the Wh figure in system info is pulled from the old cell's EEPROM-rated value, which the BIOS cached before the swap. The replacement cell is rated at 76.96Wh (14.8V × 5200mAh). After the battery learn cycle completes — one full discharge to hibernate, then a full uninterrupted charge — the reported Wh figure will update to reflect the actual new cell data.

The NP8258 stops charging at 80% and won't go higher regardless of how long it's plugged in — is this a faulty cell?

This is almost always a BIOS-controlled charge limit, not a cell fault. Sager and many OEM partners ship notebooks with a battery conservation mode enabled that caps charging at 80% to reduce long-term cell wear. Check the Sager Control Center or power management utility for a "Battery Charge Limit" or "Conservation Mode" toggle and disable it. Once off, the cell will charge to 100%.

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