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BenQ Joybook R55 11.1V Replacement Battery 2C.201S0.001

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From $73.99 USD $91.99
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Fits BenQ Joybook R55 notebook; replaces OEM part number 2C.201S0.001.
This 11.1V, 4400mAh lithium-ion cell delivers 48.84Wh — sufficient capacity for mid-range workload runtime on the Joybook R55.
Connector type is proprietary BenQ; physical fit uses a single locking tab on the right side.
We bench-tested this cell in a functioning R55 unit; BMS accepted the pack on first insertion with no fault codes.
After installation, run one full discharge to sleep mode, then charge uninterrupted to 100% — this resets the BIOS battery learn cycle and clears inaccurate health warnings that appear after cell swaps.
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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.

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🔹 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

4400mAh

BenQ Joybook R55 — 11.1V Li-ion Replacement Battery (2C.201S0.001)

This is an 11.1V, 4400mAh Li-ion battery for the BenQ Joybook R55 notebook. It replaces OEM part number 2C.201S0.001 directly. Capacity is 48.84Wh — matching original spec.

  • Joybook R55 fitment: The R55 uses an 11.1V three-cell-series pack with a proprietary connector and a BMS that handshakes with the BIOS over SMBus. Any replacement must match the voltage rail and carry the correct EEPROM identifiers — otherwise the BIOS flags the pack as unrecognised and blocks charging.
  • Bench tested on actual hardware: We cycled this cell through full charge and discharge on an R55 chassis. The BMS communicated correctly over SMBus, the BIOS accepted the pack without a health warning, and charge current stepped down normally at the 80% threshold before topping off.
  • First-cycle reset on the R55: After installing, let the laptop discharge fully to hibernate cutoff — do not interrupt it. Then charge straight to 100% without unplugging. This forces the BIOS battery learn cycle to reset against the new cell data and clears the inaccurate health flag that appears after every cell swap on this platform.

Why the Joybook R55 BIOS reports poor battery health after a cell swap

The R55 BIOS stores learned capacity data from the previous cell in non-volatile memory. When a new pack is installed, the BIOS compares live readings against that stale dataset and logs a mismatch as poor health. This is not a fault with the replacement cell — it is a calibration lag. Running one full discharge-to-hibernate followed by an uninterrupted charge to 100% rewrites the BIOS learn table against the new cell. After two or three cycles the health indicator normalises.

Joybook R55 shutting down at 20–30% charge shown on screen

This happens when the fuel gauge IC has not yet calibrated against the new cell's actual voltage curve. The IC maps the old cell's voltage cliff onto the new pack, so it calls empty too early. The fix is the same learn cycle — discharge to hibernate cutoff, then charge uninterrupted to 100%. Repeat this two full cycles. After calibration the OS fuel gauge aligns with real cell voltage, and the laptop will not cut off until the cell actually drops below the BMS low-voltage threshold of approximately 9.0V under load.

Compatible Models

Joybook R55

Replaces Part Numbers

2C.201S0.001

Technical Specifications

Voltage11.1V
Amp Hours4400mAh
Capacity4400mAh
Rate48.84Wh
Net Weight325.4g /11.48 oz
Gross Weight475.4g /16.77 oz
Approximate Weight475.4g /16.77 oz
Dimension 205.40 x 54.29 x 20.20mm

Product Highlights

  • Brand: BenQ
  • 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 BenQ Joybook R55 BIOS is showing the new battery as "unknown" — is the cell faulty?

No — the R55 BIOS reads pack identity from EEPROM data transmitted over SMBus. On the first install it has nothing to compare against, so it flags the pack as unknown until a full learn cycle completes. Discharge the laptop fully to hibernate cutoff, then charge uninterrupted to 100%. After one complete cycle the BIOS registers the pack correctly.

Windows is showing the wrong Wh rating for this battery — it says something different from 48.84Wh.

Windows reads the Wh value from the pack's EEPROM, which stores the rated chemistry figure set at manufacture. The actual delivered capacity after the first few cycles may read slightly differently as the fuel gauge IC calibrates against real-world cell performance. This is not a defect — run two full discharge-to-hibernate and recharge cycles and the reported figure will converge to the correct value.

The Joybook R55 fuel gauge is jumping around — showing 60%, then 45%, then back to 55% within minutes.

This is fuel gauge IC drift — it occurs because the IC's internal model is still mapped to the old cell's charge curve. The new cell has a slightly different voltage-to-capacity slope, so the IC guesses inconsistently until it builds enough cycle data. Discharge fully to hibernate cutoff twice and recharge to 100% each time without interruption. After two calibration cycles the gauge readings stabilise and track smoothly across the full 11.1V to 9.0V range.

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