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C31-S551 Asus VivoBook S551L Replacement Battery 11.1V 4500mAh

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From $75.99 USD $93.99
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Fits Asus VivoBook S551L, S551LA, S551LB ultrabooks; replaces OEM part C31-S551 and 3ICP7/65/80.
11.1V 4500mAh Li-Polymer cell matches original capacity and voltage signature for this chassis.
Connector is a flat three-pin JST-type plug; slides into the battery tray with locking tab on left edge.
We ran full charge-discharge cycles on a bench VivoBook S551LB; BMS throttled discharge at expected voltage curve with no early cutoff.
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.
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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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

4500mAh

Asus VivoBook S551L Series — 11.1V Li-Polymer Replacement Battery (C31-S551)

This 11.1V, 4500mAh Li-Polymer battery replaces the OEM C31-S551 cell in the Asus VivoBook S551L, S551LA, and S551LB notebooks. It fits the ultrabook-style chassis without modification and connects via the original three-cell connector. Capacity is 4500mAh (49.95Wh) — matching the stock specification.

  • S551L platform fit: The S551L, S551LA, and S551LB share the same 11.1V three-cell Li-Polymer architecture, connector pinout, and BMS handshake protocol. One cell covers all three variants because the voltage rail and communication interface are identical across the platform.
  • Bench tested on actual hardware: We cycled this cell through full charge and discharge on the S551LB platform. The BMS negotiated correctly with the ASUS EC firmware — no charging errors, no ACPI fault codes, and the fuel gauge updated continuously through each cycle.
  • Post-install calibration for the S551L: After fitting this cell, run the laptop down to hibernate cutoff under normal use — screen on, applications running — 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.

Why the S551L BIOS reports poor battery health after a cell swap

The S551L stores capacity history and cycle count data in the battery's EEPROM. When a new cell goes in, that EEPROM is blank or carries factory defaults the BIOS does not recognise as current. The embedded controller reads this as a degraded or unknown cell and flags poor health immediately. Running one full discharge-to-hibernate then an uninterrupted full charge writes new baseline data to the EEPROM and clears the flag. After two to three cycles the health reading stabilises to accurate.

Laptop shuts down at 20–30% charge shown on the S551L

This happens when the fuel gauge IC has not yet calibrated against the new cell's voltage curve. The old cell's curve is still cached, so the OS shows 25% while the actual cell voltage has already dropped below the safe cutoff threshold under CPU and display load. The laptop shuts down to protect the cell — not because the battery is faulty. Run two full discharge-to-hibernate cycles followed by uninterrupted full charges, and the fuel gauge IC recalibrates to the new cell. The cutoff point drops back to below 5% reported charge.

Compatible Models

VivoBook S551L VivoBook S551LA VivoBook S551LB VivoBook S551LB-CJ026H VivoBook S551LB-CJ045H VivoBook V551LA-DH51T VivoBook K551LB-XX171H Vivobook A551LB-XX233H VivoBook K551LB-XX164D S551LB VivoBook K551LB-XX258D VivoBook A551LB S551LA VIVOBOOK S551LC Vivobook A551LB-XX317H VivoBook K551LB-XX202D VivoBook A551LB-XX134H VivoBook K551LB-XX210H VivoBook V551LA-DS71T VivoBook K551LB-XX252D S551L VivoBook V551LB-DB71T VivoBook S551LB-CJ081H VivoBook A551LB-XX234H S551LB-CJ045H S551LB-CJ026H VivoBook V551LB-SH71T VivoBook V551LB VivoBook V551LA V551LA-DH51T VivoBook V551L V551L

Replaces Part Numbers

C31-S551 3ICP7/65/80 S551LB-CJ046H

Technical Specifications

Voltage11.1V
Amp Hours4500mAh
Capacity4500mAh
Rate49.95Wh
Net Weight267g /9.42 oz
Gross Weight407g /14.36 oz
Approximate Weight407g /14.36 oz
Dimension 209.56 x 109.38 x 9.70mm

Product Highlights

  • Brand: Asus
  • 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 S551L shows the battery as 0% or "unknown" right after installing a new cell — what's wrong?

The ASUS embedded controller reads capacity history and cycle count from the battery's EEPROM. A fresh cell has blank or factory-default EEPROM data, which the BIOS flags as an unrecognised or failed battery. This is not a fault with the cell. Boot the laptop on AC power, let Windows or the EC initialise, then run one full discharge to hibernate followed by a full uninterrupted charge — the BIOS will register the cell and the 0% or unknown reading will clear.

Windows is reporting this battery's energy capacity as wrong — it shows a different Wh rating than the 49.95Wh spec. Why?

Windows reads the Wh rating directly from the EEPROM embedded in the battery. The value stored there reflects the OEM's rated chemistry specification, which can differ slightly from the actual measured capacity of a replacement cell. This is a data field mismatch, not a capacity defect. After two full calibration cycles — full discharge to hibernate, then full charge to 100% — the fuel gauge IC overwrites the cached estimate with a measured value and the reported Wh figure normalises.

The S551L stops charging at 80% and won't go higher — is the replacement battery defective?

In most cases this is the ASUS Battery Health Charging feature active in the BIOS or MyASUS app, not a battery fault. ASUS ships several S551L firmware builds with a charge limit set to 80% to reduce cell stress during AC-connected use. Open the MyASUS application or enter the BIOS power settings and check whether Battery Health Charging is enabled — switching it to Full Capacity mode releases the 80% ceiling immediately. If that setting is already off, check that the AC adapter output is stable at 19V before concluding there is a cell issue.

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