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Hyperdata 8640D 14.8V Replacement Battery 4400mAh Li-ion

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From $80.99 USD $99.99
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Fits Hyperdata 8640D, 8640D4, 8640DH, 8640SH notebooks; replaces OEM part 442673400015 and equivalent cross-references.
14.8V, 4400mAh lithium-ion delivers 65.12Wh for full-day portable operation on this ultrabook platform.
Connector seats into the proprietary slot with positive latch; verify orientation before closing the retention clip.
We bench-tested against 8640D reference unit; BMS stabilized voltage under sustained CPU and display load with clean charge curve on first cycle.
After installation, run one full discharge to hibernation cutoff, then charge uninterrupted to 100% — this resets the BIOS battery learn cycle and clears inaccurate health warnings that appear after cell swaps on this platform.
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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

4400mAh

Hyperdata 8640D Series — 14.8V Li-ion Replacement Battery (442673400015)

This 14.8V, 4400mAh (65.12Wh) Li-ion battery replaces the original pack in the Hyperdata 8640D, 8640D4, 8640DH, and 8640SH laptops. It restores portable operation when the original cell has degraded or failed entirely. Voltage and connector match the OEM spec exactly — no adapter or modification needed.

  • 8640D family compatibility: The 8640D, 8640D4, 8640DH, and 8640SH all share the same 14.8V battery bay, connector pinout, and BMS handshake protocol — which is why a single cell covers all four variants without modification.
  • Bench tested on actual hardware: We cycled this cell through full charge and discharge on the 8640D platform. The BMS communicated correctly with the system, reported charge state without fault codes, and held voltage steadily across the discharge curve.
  • First-cycle calibration after swap: After installing, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on this platform.

BIOS reporting poor battery health immediately after fitting a new cell

The 8640D's BIOS reads health data from EEPROM registers inside the battery pack. When a new cell is installed, those registers don't match the learned discharge profile stored from the old cell. The BIOS flags this mismatch as poor health — even though the new cell is physically fine. Running the battery learn cycle (full discharge to hibernate-cutoff, then uninterrupted charge to 100%) forces the BIOS to rewrite its baseline against the new cell's actual chemistry.

Laptop shutting down at 20–30% shown on the fuel gauge

This is a voltage cliff problem, not a calibration issue. Under combined CPU and display load, the cell voltage drops faster than the fuel gauge IC can track — the system hits the low-voltage cutoff threshold while the gauge still shows charge remaining. The fuel gauge IC needs two or three full calibration cycles against the new cell before its predictions stabilise. After calibration cycles, the shutdown threshold should align with readings below 10%. If it persists past three cycles, check that the BIOS power profile isn't set to an aggressive low-battery cutoff above 15V.

Compatible Models

8640D 8640D4 8640DH 8640SH

Replaces Part Numbers

442673400015 40004852 40004852(PS) 442673400003 442673400004 442673400008 442673400016 442673400027 442673400028 442673400029 442674600002 442679900001 442679900002 442679900004 442679900007 442680700001 821561 CGR-B/T19SE-MSL NBP001310-00 7004690000 7022560000 442679900003 4426746100001

Technical Specifications

Voltage14.8V
Amp Hours4400mAh
Capacity4400mAh
Rate65.12Wh
Gross Weight270g /9.52 oz
Approximate Weight270g /9.52 oz
Dimension 274.00 x 48.00 x 20.00mm

Product Highlights

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

Frequently Asked Questions

The Hyperdata 8640D shows "0% available (plugged in, not charging)" with the new battery installed — what's happening?

This usually means the BIOS hasn't initialised communication with the new cell's EEPROM yet. Shut the laptop down completely, remove the battery, hold the power button for 15 seconds to drain residual charge from the board, then reinstall the battery and boot. If the gauge still reads 0%, run a full discharge to hibernate-cutoff followed by an uninterrupted charge to 100% — that forces the fuel gauge IC to re-sync with the new cell.

Windows is showing the wrong Wh rating for the new battery — it says 48Wh but the battery is rated 65.12Wh. Is the cell faulty?

No — this is an EEPROM data mismatch. The Wh value Windows displays is pulled from the battery's EEPROM register, which on some replacement cells is pre-programmed to a different rated chemistry configuration. The actual deliverable energy is not affected. After one complete discharge-to-hibernate and full recharge cycle, Windows re-reads the register and typically corrects the displayed figure to match the cell's actual 65.12Wh rating.

The fuel gauge on the 8640D jumps from 60% to 15% within minutes on the new battery — is the cell defective?

The fuel gauge IC on the 8640D needs several full cycles to build an accurate discharge model for the new cell's chemistry. On the first two or three cycles, large jumps in reported percentage are normal — the IC is still mapping voltage curves from the old cell's profile. Run three consecutive full discharges to hibernate-cutoff followed by uninterrupted charges to 100%. By the third cycle, the gauge reading should track steadily without sudden drops.

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