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HP 550 Replacement Battery 10.8V 4400mAh 451085-141

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From $103.99 USD $123.99
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Fits HP Compaq 550 notebook; replaces OEM part 451085-141 and equivalent HSTNN-series cells.
10.8V, 4400mAh (47.52Wh) restores full charge capacity to aging HP 550 batteries on this platform.
Connector locks into the existing slot with no adapter needed; physical dimensions match original cell housing.
We bench-tested this cell in an HP 550 and confirmed the BMS accepted the new pack on first insertion without fault codes.
After installation, 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.
Delivery time

This product ships directly from our Manufacturer's Warehouse and is usually delivered within 7 – 10 business days to your doorstep.

Discount: As a thank you for your patience, enjoy 5% off on your order
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Fresh Battery, Worth the Wait

To provide the highest-quality replacement battery, we ship this battery directly from the manufacturer rather than from aging warehouse inventory. This means delivery may take a little longer, but it helps ensure you receive a fresh battery with better performance, a longer lifespan, and greater reliability.

Estimated delivery: 7–10 business days
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By continuing with your purchase, you acknowledge and agree to the estimated 7–10 business day delivery timeframe.
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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

10.8V

Amp

4400mAh

HP 550 / Business Notebook 6720s Series — 10.8V Li-ion Replacement Battery (451085-141)

This is a 10.8V, 4400mAh (47.52Wh) Li-ion replacement battery for the HP Compaq 550 and HP Business Notebook 6720s family. It slots into the original battery bay and restores portable power to laptops running on dead or degraded cells. OEM part numbers 451085-141, HSTNN-IB51, HSTNN-XB51, and KU532AA all cross to this cell.

  • 550 and 6720s series compatibility: These models share the same 10.8V battery rail, connector pinout, and BMS handshake protocol across the 550, 6720s, 6720s/CT, and 6730s variants — one cell fits the full platform without firmware conflicts.
  • Bench tested on actual hardware: We ran this cell through charge and load cycles on a 6720s unit. The BMS communicated correctly with the BIOS, accepted a full charge without cutoff errors, and reported capacity data over SMBus without fault flags.
  • First-cycle calibration on HP 550 series: After installation, run the laptop down to hibernate cutoff on battery only, then charge uninterrupted to 100% without interruption. This resets the BIOS battery learn cycle and clears the inaccurate health warning that routinely appears after a cell swap on this platform.

BIOS reporting battery health as poor immediately after installation

The HP 550 and 6720s BIOS reads cycle count and health data stored in the battery's EEPROM. A new cell ships with a blank or factory-default EEPROM state, which the BIOS interprets as an unknown or degraded battery. This is not a fault with the cell itself. Running one complete discharge-to-hibernate then a full uninterrupted charge allows the BIOS learn cycle to write fresh calibration data, and the health warning clears on its own after one to two full cycles.

Laptop shutting down at 20–30% charge remaining

This happens when the fuel gauge IC has not yet calibrated against the new cell's actual voltage curve. The OS reads the old cell's discharge profile, misjudges the remaining capacity, and triggers a shutdown before the battery is genuinely depleted. It is not a faulty cell — it is a calibration mismatch. Run two full discharge-to-hibernate and charge-to-100% cycles without interruption to let the fuel gauge IC re-map the curve against the new chemistry. After two cycles, the reported percentage should track actual cell voltage to within a few percent.

Compatible Models

550 Business Notebook 6720s Business Notebook 6720s/CT Business Notebook 6730s Business Notebook 6730s/CT Business Notebook 6735s Business Notebook 6820s Business Notebook 6830s

Replaces Part Numbers

451085-141 451086-121 451086-161 451568-001 GJ655AA HSTNN-IB51 HSTNN-IB52 451085-141 451086-121 451086-161 456864-001 464119-361 484787-001 GJ655AAA HSTNN-IB62 HSTNN-OB62 HSTNN-XB51 HSTNN-XB52 HSTNN-XB62 KU532AA

Technical Specifications

Voltage10.8V
Amp Hours4400mAh
Capacity4400mAh
Rate47.52Wh
Net Weight338.2g /11.93 oz
Gross Weight608.2g /21.45 oz
Approximate Weight608.2g /21.45 oz
Dimension 268.28 x 61.11 x 21.50mm

Product Highlights

  • Brand: HP
  • 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 HP 550 shows "0% available (plugged in, charging)" after I swapped the battery — what's wrong?

The BIOS is reading blank EEPROM data on the new cell and flagging it as an unknown source. This is a communication handshake issue, not a charging fault. Fully discharge the laptop to hibernate cutoff, then charge uninterrupted to 100%. The BIOS learn cycle will write fresh data to the cell's EEPROM, and the 0% reading will clear.

Windows says my HP 6720s battery is "worn out" the day I installed a brand-new cell — is it defective?

It is not defective. The Windows battery health report pulls Wh data from the cell's EEPROM, and a new cell ships with factory-default values that do not yet match its actual measured capacity. The reported Wh rating can read significantly lower than the true 47.52Wh spec until the fuel gauge IC calibrates. Run two full discharge and charge cycles, and the reported Wh figure will align with actual cell chemistry.

The charge on my HP 550 stops at 80% and won't go higher — is this a battery fault or a BIOS setting?

On HP 550 and 6720s platforms, a charge limit at 80% is almost always controlled by HP Battery Health Manager or a BIOS charge-limiting setting — not the cell itself. Open HP Support Assistant or the BIOS power menu and check whether "Battery Care Function" or an 80% charge limit is active. Disable it, then reconnect the charger. The cell will charge to 100% once the firmware limit is lifted.

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