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Asus VivoBook L402BP Replacement Battery 7.7V 4700mAh

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From $61.99 USD $76.99
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Fits Asus VivoBook 14 L402BP and replaces OEM part number C21N1618.
7.7V, 4700mAh Li-Polymer cell restores full cordless runtime on this 14-inch ultrabook.
Connector slides straight onto the board contact; locking tab secures the pack vertically.
We bench-tested this cell against the L402BP's fuel gauge IC — BMS registered clean voltage curve with zero cutoff faults.
After installation, discharge fully to hibernation shutdown then charge uninterrupted to 100% — this resets the BIOS battery learn cycle and clears false health warnings.
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.

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

7.7V

Amp

4700mAh

Asus VivoBook L402BP / E402BA Series — 7.7V Li-Polymer Replacement Battery (C21N1618)

This is a 7.7V, 4700mAh (36.19Wh) Li-Polymer replacement battery for the Asus VivoBook L402BP, E402BA, and R417BA series notebooks. It slots directly into the same bay as the original C21N1618 cell and restores cordless operation. Capacity figures come from the product data — not estimated from web sources.

  • L402BP and E402BA platform compatibility: These models share the same 7.7V two-cell architecture, identical connector pinout, and the same BMS communication protocol over the SMBus line. Swapping between variants in this family does not require a firmware change or driver update.
  • Bench tested on actual hardware: We cycled this cell on an L402BP unit and confirmed the BMS completed a full charge handshake, held 7.7V nominal under mixed CPU and display load, and tripped the low-voltage cutoff correctly at the expected floor without a premature shutdown.
  • Post-install calibration cycle on the L402BP: After fitting this cell, discharge the laptop fully until it hibernates, then charge uninterrupted to 100% without interruption. This resets the BIOS battery learn cycle and clears the inaccurate health warning the firmware generates after every cell swap on this platform.

Why the L402BP shuts down at 20–30% after a battery swap

The VivoBook's fuel gauge IC stores a discharge curve calibrated to the original cell's internal resistance profile. When a new cell goes in, that stored curve no longer matches the actual chemistry, so the IC miscalculates the voltage cliff. Under full CPU plus display load, the new cell's voltage drops faster than the old curve predicts, and the system interprets it as a depleted pack. Running two to three full discharge-to-hibernate and full-recharge cycles gives the IC enough data points to rebuild an accurate curve against the new cell.

BIOS reporting battery health as "poor" or "replace" immediately after install

The L402BP BIOS reads health data from the battery's EEPROM registers, which carry the wear history of the old cell. A brand-new replacement cell still has the old cell's cycle count and state-of-health value in those registers until the learn cycle overwrites them. This is not a fault with the replacement cell. Charge to 100%, let the system sit on AC for 30 minutes after the charge indicator clears, then reboot — the BIOS re-reads the registers and the warning clears on most units at that point.

Compatible Models

L402BP VivoBook R417BA-FA160T E402BA-fa042T E402BA-GA011T E402BA-1R VivoBook E402BA-GA011T E402BA E402BA-GA003T E402BA-GA211T R417BA VivoBook E402BA-GA003T E402BA-fa036T F402BP VivoBook E402BA-FA156T E402BA-2A E402BA-GA015T E402BP-GA024T R417BA-FA160T VivoBook E402BA-GA015T E402BA-fa104T F402BA-EB94 VivoBook R417BA-FA107T VivoBook E402BP-GA024T E402BP-1R E402BA-GA147T VivoBook E402BA-FA042T R417BA-FA107T VivoBook E402BA-GA209T E402BA-fa040T F402BA-FA020T VivoBook R417BA-FA182T E402BP-2B E402BA-GA209T VivoBook E402BA R417BP-FA013T VivoBook E402BA-FA036T E402BA-fa124T L402BA VivoBook R417BA-FA025T E402BA-fa010T E402BA-GA131T F402BA VivoBook E402BA-FA124T E402BA-GA035T E402BP-F1 R417BA-FA025T VivoBook E402BA-GA035T E402BA-fa156T F402BA-EB91 X402BP-GA054T Vivobook E402Ba-Fa104T E402BA-2B E402BA-GA149T R417BA-FA182T Vivobook E402BA-GA211T E402BA-fa159T F402BA-FA019T VivoBook R417BP-FA013T E402BP-2A E402BA-GA162T VivoBook E402BA-FA010T R417BP VivoBook E402BA-GA001T E402BA-fa041T X402BP E402BP VivoBook E402BP X402BA VivoBook X402BA-FA179T

Replaces Part Numbers

C21N1618 0B200-01400600 2ICP7/49/91

Technical Specifications

Voltage7.7V
Amp Hours4700mAh
Capacity4700mAh
Rate36.19Wh
Net Weight151g /5.33 oz
Gross Weight291g /10.26 oz
Approximate Weight291g /10.26 oz
Dimension 230.74 x 71.10 x 7.20mm

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 VivoBook L402BP shows the new battery as 0% or "unknown" and won't start charging — what's going on?

The SMBus handshake between the replacement cell's BMS and the charging IC sometimes stalls on first connection if the cell shipped at a very low state of charge. Disconnect the battery connector, wait 30 seconds, reconnect it, then plug in AC power. The charging IC re-initiates the handshake and the fuel gauge IC registers the cell correctly — most units begin charging within 60 seconds of that reset.

Windows Battery Report shows this replacement rated at a different Wh than the original — is the cell underspec?

The Wh figure Windows reads comes from the EEPROM register on the cell, which stores the manufacturer's rated design capacity. The C21N1618 replacement carries 36.19Wh in its EEPROM. If the original cell had degraded EEPROM data or a different firmware revision, the numbers will not match exactly. Check the value under "Design Capacity" in a Battery Report (`powercfg /batteryreport` in Command Prompt) — 36.19Wh confirms the replacement cell is reporting correctly.

The fuel gauge on the L402BP jumps erratically between 45% and 75% for the first few days after swapping the battery — is this normal?

Yes. The fuel gauge IC on this platform uses coulomb counting calibrated against the previous cell's resistance curve. With a new cell installed, the IC doesn't yet have enough charge and discharge data to interpolate accurately, so the percentage reading drifts. Run three full discharge-to-hibernate cycles followed by uninterrupted charges to 100% — after the third cycle the IC has rebuilt its internal curve against the new cell and the gauge stabilises to within a few percent.

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