Welcome to our store. Your trusted source for batteries and power solutions. Learn more

For support or quotes: sales@batteryweb.com
WELCOME5
BatteryWeb

Asus X456 C21N1508 Replacement Battery 7.6V 4800mAh

Up to 20% off
New arrival
From $58.99 USD $73.99
Shipping calculated at checkout.
Fits Asus X456, X456UJ, X456UV, and X456UF laptops — replaces OEM part numbers C21N1508, 0B200-01740100, and 0B200-01740000.
Delivers 7.6V and 4800mAh (36.48Wh) to restore full portable runtime on your X456 notebook.
Connector slots into the original battery bay with no modifications — physical dimensions and locking tab match factory pack exactly.
We bench-tested this cell on X456UJ hardware; the BMS accepted charge current without cutoff and held voltage under sustained CPU load.
After installation, run one full discharge to sleep mode then charge uninterrupted to 100% — this resets the BIOS battery learn cycle and clears false health warnings that appear after every cell swap.
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
WECARE5

Please Confirm Delivery Timeline

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
4.8
★★★★★
★★★★★
Average Customer Rating
By continuing with your purchase, you acknowledge and agree to the estimated 7–10 business day delivery timeframe.
Visa Mastercard American Express PayPal Apple Pay Google Pay Shop Pay Discover Klarna Afterpay Stripe
✦

Check that your old battery model number and device model to match our description. This makes sure they work together.

✦

We ship your order same day if you buy it before 4 PM EST.

Warranty

Let customers speak for us

from 12 reviews

I'm writing this review to express my deep gratitude and appreciation for the quality of services provided to me by the BatteryWeb service team. I visited BatteryWeb to purchase a replacement battery for my Remington R9 razor. The staff was very responsive and I was really impressed with their willingness to help me and make the purchasing process as quick as possible. In particular I greatly appreciate the work of staff member Shane who was friendly and helpful.
In conclusion, I believe that BatteryWeb has excellent service staff who make their customers feel honored and valued.
I wish you all the best.
Sincerely,
Michael

Michael Talianker
BatteryWeb

this battery was just what I needed.

Robert Jones
BatteryWeb

Product is exactly as described and arrived quickly

Robert Jones
Rocket ES4-12 Compatible Replacement Battery

Great deal for the money.

Linda M.
BatteryWeb

It took a bit longer than expected, likely due to the holiday season, but that was understandable. So far, the battery seems to be working well!

Linda M.
MGE UPS Systems Pulsar EX 1500RT Compatible Replacement Battery By Bright Way

Excellent substitute for the original, appearing to be the perfect replacement.

Alberto J.
APC SMART-UPS RT SURTA3000RMXL3U UPS High Performance Replacement Battery Set

It was what i was looking for. Support is fast

Jaswal
WAHEGURUG - RADHASWAMI

Fast service

Mark Casias
BatteryWeb

Perfect fit

Mark Casias
STX20L-BS Battery for Harley Softail FLS FLST 1991-2017 High Performance

Works Perfectly!!

Ben Benson
Invacare 220 Scooter High Performance Medical Replacement Battery Set

Send Your Battery Photo

Expert Technician Help

Snap a photo or video of your battery and send it to us. We'll identify the exact replacement—fast and hassle-free. Our team has helped thousands of customers find the right battery quickly and easily.

POST YOUR BATTERY IMAGE
Product & Solutions Expert

Product & Solutions Expert

✉ sales@batteryweb.com

🔹 10+ Years Battery Experience 🔹 Fast & Accurate Identification

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

7.6V

Amp

4800mAh

Asus X456 Series — 7.6V Li-Polymer Replacement Battery (C21N1508)

This 7.6V, 4800mAh Li-Polymer battery replaces the original C21N1508 cell in Asus X456 series laptops, including the X456UJ, X456UV, and X456UF. It fits the physical bay and connector without modification. Capacity is 36.48Wh — matching the original specification.

  • X456 series fit: The X456UJ, X456UV, and X456UF share the same 7.6V two-cell Li-Polymer architecture, the same connector pinout, and the same BMS communication protocol — that is why one part number covers the full range.
  • Bench tested on actual hardware: We cycled this cell through charge and discharge on an X456UJ board. The BMS negotiated charge current correctly, the fuel gauge IC registered the new cell, and the protection circuit tripped at the expected low-voltage threshold.
  • First cycle after installation: After fitting this battery, run the laptop on battery power until it hibernates on its own, then charge uninterrupted to 100%. This forces the BIOS battery learn cycle to reset against the new cell and clears the inaccurate health warning that appears after every cell swap.

Why the X456 shuts down at 20–30% charge shown after a battery swap

The X456 uses a fuel gauge IC that builds its capacity model from repeated charge and discharge cycles. When a new cell goes in, the IC still references the old cell's learned curve. Under full CPU and display load, actual cell voltage drops faster than the IC predicts. The system hits the hardware low-voltage cutoff while the gauge still shows 20–30% remaining. Two to three full discharge-to-hibernate, charge-to-100% cycles recalibrate the IC against the new cell and the early shutdowns stop.

BIOS reports battery health as "poor" or capacity as 0% immediately after fitting a new cell

The BIOS reads health data from EEPROM registers embedded in the battery's BMS — not from live voltage. When the old cell's EEPROM data differs from the new cell's reported parameters, the BIOS flags a mismatch and displays a poor health or unknown warning. This is not a fault with the replacement cell. Run one complete learn cycle — discharge to hibernate cutoff, then charge uninterrupted to 100% — and the BIOS will update its health register to reflect the new cell's actual state.

Compatible Models

X456 X456UJ X456UV X456UF X456UA X456UR X456UF-3F X456UV-1C X456UF-WX057T VivoBook X456UF R457UJ R457UV-FA086T X456UB-1A X456UR-1B X456UA-WX015T X456UR-FA180D R457UA-WX195T R457UR-WX053T X456UJ-1A X456UV-3G X456UQ-GA055T VivoBook X456UQ R457UQ-WX049T X456UB-1C X456UR-3F X456UA-WX016 X456UV-GA063T R457UB R457UV-GA069T X456UA-1A X456UJ-1C X456UQ-1A X456UQ-WX005T VivoBook X456UV R457UQ-FA117T X456UF-1A X456UB-WX009T X456UR-FA159D R457UB-WX037T R457UV-GA068T X456UA-1C X456UJ-3G X456UQ-1C X456UQ-WX034T X456UF-3G R457UR X456UF-1C X456UV-1B X456UF-WX012 VivoBook X456UB R457UF R457UV-GA055T X456UR-1A X456UQ-3G X456UR-GA154D R457UA-FA135T R457UR-FA174T X456UV-3F X456UJ-BS71-CB VivoBook X456UJ R457UQ R457UV-FA047T X456UB-1B X456UR-1C X456UA-WX006T X456UV-GA050T R457UA-FA198T R457UV X456UJ-1B X456UQ-GA060T VivoBook X456UR R457UQ-FA066T X456UR-3G X456UA-WX121T X456UV-BB71-CB R457UB-WX024T R457UV-WX053T X456UA-1B X456UJ-3F X456UQ-1B X456UQ-WX016T X456UA-3F R457UQ-FA062T X456UF-1B X456UV-1A X456UB-WX010T VivoBook X456UA R457UB-WX022T R457UV-WX035T X456UA-3G X456UQ-3F X456UR-GA114T R457UA R457UR-WX088T X456UQ X456UB

Replaces Part Numbers

C21N1508 0B200-01740100 0B200-01740000

Technical Specifications

Voltage7.6V
Amp Hours4800mAh
Capacity4800mAh
Rate36.48Wh
Net Weight169g /5.96 oz
Gross Weight309g /10.90 oz
Approximate Weight309g /10.90 oz
Dimension 178.90 x 78.20 x 10.06mm

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 Asus X456 battery shows 0% or "unknown" in Windows right after I installed the new one — is the cell dead?

The fuel gauge IC on the X456 inherits EEPROM data from the old cell and cannot immediately read the new cell's state accurately. The 0% or "unknown" reading is an IC calibration gap, not a dead cell. Discharge the laptop on battery power until it hibernates, then charge uninterrupted to 100%. After one full cycle the fuel gauge resets and the reading corrects itself.

The Asus X456 battery gauge is jumping around — showing 60%, then 45%, then 70% within minutes — what is causing that?

The fuel gauge IC on the X456 uses a learned capacity model built up over multiple cycles. With a new cell installed, that model is built against a cell that no longer exists, so the IC's predictions are erratic under varying load. This is normal for the first two to three cycles. Run two complete discharge-to-hibernate, charge-to-100% cycles and the gauge will stabilise.

Windows shows the Asus X456 battery Wh rating as lower than the 36.48Wh spec on the listing — is it mislabelled?

The Wh figure Windows reports is pulled from the EEPROM's design-capacity register, which can differ from the actual chemistry capacity of the replacement cell during early cycles. The cell itself is rated at 36.48Wh — the discrepancy is a register mismatch, not a capacity shortfall. After two or three full calibration cycles the reported figure will align more closely with the rated 36.48Wh as the fuel gauge IC updates its learned values.

Payment & Security

Payment methods

  • American Express
  • Apple Pay
  • Bancontact
  • Diners Club
  • Discover
  • Google Pay
  • Mastercard
  • PayPal
  • Shop Pay
  • Visa

Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.

Related Products

Asus X456 Replacement Battery, 7.6V, 4800mAh, Li-Polymer 1

Engineered for Performance. Built to Last.

Check out our top-rated selection of reliable products built to last. We offer high-quality options that deliver consistent performance for all your needs.

Our Collections