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Toshiba Qosmio X770 Replacement Battery 14.4V PA3928U-1BRS

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From $104.99 USD $128.99
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Replaces Toshiba PA3928U-1BRS, PABAS248, 4IMR19/65-2 battery for Qosmio X770 notebooks.
14.4V and 4400mAh deliver 63.36Wh — matches OEM output for sustained gaming and multimedia workloads.
Connector locks into the Qosmio X770 battery slot with keyed plastic guide and retention tab.
We bench-tested this cell in an X770 frame; BMS initialized without fault codes and held voltage under CPU load.
After installation, run one full discharge to hibernation cutoff then charge uninterrupted to 100% — this resets the BIOS battery learn cycle and clears the false low-health warning that appears after every cell swap.
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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.

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⚠️ 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

14.4V

Amp

4400mAh

Toshiba Qosmio X770 Series — 14.4V Li-ion Replacement Battery (PA3928U-1BRS)

This is a 14.4V, 4400mAh Li-ion replacement battery for the Toshiba Qosmio X770 gaming and multimedia notebook. It replaces OEM part numbers PA3928U-1BRS, PABAS248, and 4IMR19/65-2. Total energy capacity is 63.36Wh.

  • Qosmio X770 series fit: The X770, X770-107, X770-11C, X770-136, and 17 additional X770 variants all share the same battery bay dimensions, 14.4V voltage rail, and SMBUS connector pinout. One cell fits the entire run of that chassis.
  • Bench tested on actual hardware: We ran this cell through charge-discharge cycles on an X770 unit. The BMS communicated correctly over SMBUS, the BIOS accepted the cell without unknown-device errors, and charge termination triggered cleanly at full capacity.
  • First-cycle learn reset on the X770: After fitting this cell, run the laptop on battery until it hibernates at low charge cutoff, then charge uninterrupted to 100%. The X770 BIOS runs a battery learn cycle against this data — skipping it leaves the fuel gauge IC working from the old cell's EEPROM figures, which causes wildly inaccurate state-of-charge readings for the first several uses.

Why the X770 BIOS flags a new battery as poor health

The Qosmio X770 stores battery health data in EEPROM on the original cell's protection circuit. When a new cell goes in, the BIOS reads no matching cycle count or rated-capacity record and flags the battery as degraded or unknown. This is a data mismatch — not a fault with the replacement cell. Running one full discharge-to-hibernate followed by an uninterrupted charge cycle writes new reference data to the BIOS learn table and clears the warning on most X770 firmware versions.

X770 shutting down at 20–30% charge shown on screen

The X770 pairs a high-draw CPU and discrete GPU that spike combined load far above idle draw. At 20–30% state-of-charge, a degraded or uncalibrated cell hits a voltage cliff — pack voltage drops below the BMS cutoff threshold under that load even though the fuel gauge still shows capacity remaining. The system interprets the voltage drop as an emergency and cuts power instantly. After installing a new cell, complete the learn cycle described above so the fuel gauge IC recalibrates its discharge curve against the fresh chemistry. Once calibrated, the gauge and the BMS threshold align, and the false shutdown clears.

Compatible Models

Qosmio X770 Qosmio X770-107 Qosmio X770-11C Qosmio X770-136 Qosmio X770-BT5G23 Qosmio X770-BT5G24 Qosmio X770-ST4N04 Qosmio X775 Qosmio X775-3DV78 Qosmio X775-3DV80 Qosmio X775-3DV82 Qosmio X775-Q7170 Qosmio X775-Q7270 Qosmio X775-Q7272 Qosmio X775-Q7273 Qosmio X775-Q7275 Qosmio X775-Q7380 Qosmio X775-Q7384 Qosmio X775-Q7387 Qosmio X770 3D Qosmio X775 3D

Replaces Part Numbers

PA3928U-1BRS PABAS248 4IMR19/65-2

Technical Specifications

Voltage14.4V
Amp Hours4400mAh
Capacity4400mAh
Rate63.36Wh
Gross Weight180g /6.35 oz
Approximate Weight180g /6.35 oz
Dimension 205.20 x 51.70 x 42.00mm

Product Highlights

  • Brand: Toshiba
  • 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

The Qosmio X770 is showing my new battery as 0% or "unknown" in Windows — did I get a bad cell?

The X770 BIOS pulls health and capacity data from EEPROM stored on the original cell's protection circuit. A new cell has no matching record, so the system reports unknown or 0% until it runs a learn cycle. Discharge the laptop fully to hibernate cutoff, then charge uninterrupted to 100% without interruption. After that single cycle, Windows Battery Report and the BIOS health indicator should display accurate figures.

My replacement battery stops charging at around 80% and never reaches 100% — is the cell faulty?

This is almost always the Toshiba Battery Charge Mode setting in the BIOS, not the cell itself. Toshiba's firmware includes an 80% charge limit option labelled "ECO Charge" or similar, activated to reduce cell wear. Go into the BIOS at startup, locate the Battery section, and switch the charge mode from ECO to Maximum. The cell will then charge to the full 63.36Wh capacity.

System information shows the wrong Wh rating for this battery — it lists a number that doesn't match 63.36Wh.

The Wh figure shown in Windows or Toshiba utilities is read from the cell's EEPROM at first recognition, which may carry the rated value from a different chemistry or capacity variant. After one full discharge-to-hibernate and a complete uninterrupted charge back to 100%, the BIOS learn cycle updates its stored reference data. Check the reported Wh figure again after that calibration cycle — it should align with the 63.36Wh spec for this cell.

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