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Fujitsu Stylistic Q665 Replacement Battery 11.1V 3400mAh

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From $85.99 USD $105.99
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Fits Fujitsu Stylistic Q665, Q738, Q739, Q616 tablets replacing CP690859, CP690859-01, CP700540-01, FPB0326S, FPB0349S, FPCBP479 cells.
11.1V, 3400mAh Li-Polymer pack delivers 37.74Wh — sustains the Q-series hybrid's CPU and display under continuous load without mid-cycle voltage sag.
Connector seats flush into the battery slot with a single locking tab on the right edge; orient the label face toward the inside of the device housing.
We bench-tested this cell against a Stylistic Q665 motherboard; the BMS accepted the new EEPROM handshake on first charge with no fault codes or cutoff events.
On first boot after installation, discharge the tablet to automatic hibernate, 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.
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.

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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

11.1V

Amp

3400mAh

Fujitsu Stylistic Q665 / Q738 / Q739 — 11.1V Li-Polymer Replacement Battery (CP690859)

This is an 11.1V, 3400mAh (37.74Wh) Li-Polymer replacement battery for the Fujitsu Stylistic Q665, Q738, Q739, and Q616 series detachable tablets. It replaces OEM part numbers CP690859, CP690859-01, CP700540-01, FPB0326S, FPB0349S, and FPCBP479. Install it when the original cell has degraded, lost significant capacity, or stopped holding charge altogether.

  • Stylistic Q-series compatibility: The Q665, Q738, Q739, and Q616 all share the same 11.1V cell architecture, connector pinout, and BMS handshake protocol — that is why one part number covers all four platforms.
  • Bench tested on actual hardware: We cycled this cell through charge, full discharge to hibernate cutoff, and a second full charge. The BMS reported correct voltage at each stage and did not trip the protection circuit under sustained load.
  • First-cycle calibration on the Stylistic Q-series: After fitting this battery, 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 these tablets.

Why the Stylistic Q665 shuts down at 20–30% after a battery swap

The fuel gauge IC still holds voltage-curve data from the old, degraded cell. When the new cell reaches a voltage point that the old profile mapped to 20–30% remaining, the firmware calls a low-voltage shutdown — even though the new cell has capacity left. Running one full discharge-to-hibernate, then a full uninterrupted charge forces the gauge IC to relearn the new cell's actual voltage curve. After two to three cycles the shutoff point tracks correctly.

BIOS reporting battery health as poor immediately after installation

The Stylistic Q-series BIOS reads EEPROM data written by the original factory cell, including cycle count and rated Wh. A replacement cell presents different EEPROM values, which the BIOS flags as degraded or unknown health. This is not a fault with the new cell — it is a data mismatch. Run the battery learn cycle described above; on most Q-series units the health status updates to normal within one full charge cycle after calibration.

Compatible Models

Stylistic Q665 Stylistic Q739 Stylistic Q738 Stylistic Q616 Stylistic Q7311 Stylistic Q7310 Stylistic Q7312

Replaces Part Numbers

CP690859 CP690859-01 CP700540-01 FPB0326S FPB0349S FPCBP479

Technical Specifications

Voltage11.1V
Amp Hours3400mAh
Capacity3400mAh
Rate37.74Wh
Net Weight182g /6.42 oz
Gross Weight322g /11.36 oz
Approximate Weight322g /11.36 oz
Dimension 176.30 x 103.40 x 6.00mm

Product Highlights

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

Frequently Asked Questions

My Stylistic Q665 keeps shutting down at around 25% battery shown — is that the new cell failing already?

No — it is the fuel gauge IC running the old cell's voltage map against the new cell's chemistry. The old profile tells the firmware that the voltage at that point means "critically low," so it shuts down early. Run one full discharge to hibernate cutoff, then charge to 100% without interruption. After two to three cycles the gauge recalibrates and the cutoff point drops back to the correct level near 5%.

The Stylistic Q738 shows the wrong Wh rating in system info after I fitted this battery — should I be worried?

The Wh figure displayed comes from EEPROM data embedded in the original cell, not from the live cell itself. A replacement cell carries different EEPROM values, so the OS reports a mismatched Wh rating. It does not affect how the battery charges or discharges. Run the battery learn cycle — one full discharge to hibernate, then an uninterrupted charge to 100% — and the reported figure will typically align with the new cell's actual 37.74Wh rating after one or two cycles.

New battery installed in the Stylistic Q665 but charge stops at 80% and won't go higher — what is causing that?

The Fujitsu BIOS on these tablets includes a firmware-controlled charge limit that caps charging at 80% when Battery Save Mode is active. Check the Fujitsu Battery Utility or Power Management settings in Windows — there will be a "Battery Charge Mode" or "Battery Save Mode" toggle. Switch it to "Full Charge" mode. The new cell is not at fault; the 80% ceiling is a BIOS feature, not a battery or charger problem.

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