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

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

Asus A420UA Replacement Battery 7.7V 4900mAh Li-Polymer

Up to 19% off
New arrival
From $124.99 USD $153.99
Shipping calculated at checkout.
Fits Asus VivoBook 14 A420UA and replaces OEM part numbers 0B200-03200000 and C21N1819.
7.7V and 4900mAh (37.73Wh) restore full charge cycles on this 14-inch ultrabook.
Connector type is proprietary Asus; battery slides into the slot with the locking tab facing the hinge.
Bench testing shows the BMS accepts charge current immediately on first insertion with no fault delay.
After installation, discharge fully to shutdown then charge uninterrupted to 100% — this resets the BIOS battery learn cycle and clears 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

7.7V

Amp

4900mAh

Asus VivoBook 14 A420UA Series — 7.7V Li-Polymer Replacement Battery (0B200-03200000)

This 7.7V, 4900mAh (37.73Wh) lithium-polymer cell replaces the original battery in the Asus VivoBook 14 A420UA, A420UA-EK115T, F420UA, and Pro 14 R459UA, plus over 60 additional A420 and F420 variants. It matches the original connector, cell count, and BMS handshake required by the A420UA motherboard. Dimensions are 183.80 × 135.30 × 5.00mm — a direct physical match to the OEM tray.

  • A420UA and F420UA platform compatibility: These models share the same two-cell Li-Polymer configuration, 7.7V nominal rail, and C21N1819 BMS protocol. The replacement cell communicates correctly with the EC firmware on all listed variants without triggering a hardware mismatch error.
  • Bench tested on actual hardware: We ran this cell on an A420UA-EK115T under simultaneous CPU and display load. The BMS held the 7.7V rail steady through charge and discharge cycles, with thermal cutoff activating correctly at the upper limit. No false low-battery shutdowns occurred during testing.
  • Post-swap battery learn cycle: After fitting this cell, run a full discharge to hibernate cutoff, then charge uninterrupted to 100% without using the laptop. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears on the first boot after any cell replacement.

BIOS reporting poor battery health immediately after fitting a new cell

The A420UA stores battery health data in EEPROM on the embedded controller. When a new cell goes in, the EC reads the blank or mismatched EEPROM values and flags the battery as degraded — even though the cell is new. This is not a fault with the replacement. One full discharge-to-hibernate followed by an uninterrupted charge to 100% rewrites the learn cycle data. After two to three full cycles, the BIOS health indicator should read normal.

Laptop shutting down at 20–30% shown on the fuel gauge

This happens when the fuel gauge IC has not yet calibrated against the new cell's actual discharge curve. The IC still maps voltage thresholds from the old, degraded cell — so it miscalculates the remaining capacity and triggers a shutdown well before the cell is actually empty. The fix is to complete two to three full discharge-to-hibernate and uninterrupted full-charge cycles. After calibration, the gauge tracks correctly and shutdowns stop occurring above the true low-voltage cutoff, around 6.0V under load.

Compatible Models

A420UA A420UA-EK115T F420UA Pro 14 R459UA R459UA R459UA-EK138R S420UA VivoBook 14 F420FA VivoBook 14 F420FA-EB045T VivoBook 14 F420UA VivoBook 14 F420UA-BV156T VivoBook 14 F420UA-EK992T VivoBook 14 S420UA VivoBook 14 S420UA-EK021T VivoBook 14 X420FA VivoBook 14 X420FA-8202T VivoBook 14 X420FA-BV021T VivoBook 14 X420FA-BV082AT VivoBook 14 X420FA-EB035T VivoBook 14 X420FA-EB075T VivoBook 14 X420FA-EB086T VivoBook 14 X420FA-EB089T VivoBook 14 X420FA-EB148T VivoBook 14 X420FA-EB149 VivoBook 14 X420FA-EB157T VivoBook 14 X420FA-EB234T VivoBook 14 X420FA-EK037T VivoBook 14 X420FA-EK040T VivoBook 14 X420FA-EK051T VivoBook 14 X420FA-EK177T VivoBook 14 X420UA VivoBook 14 X420UA-BV083T VivoBook 14 X420UA-BV124T VivoBook 14 X420UA-BV143T VivoBook 14 X420UA-BV165T VivoBook 14 X420UA-CBI5A VivoBook 14 X420UA-EB075T VivoBook 14 X420UA-EB112T VivoBook 14 X420UA-EB113T VivoBook 14 X420UA-EB119T VivoBook 14 X420UA-EB184T VivoBook 14 X420UA-EK019T VivoBook 14 X420UA-EK019TS VivoBook 14 X420UA-EK023T VivoBook 14 X420UA-EK050T VivoBook 14 X420UA-EK053T VivoBook 14 X420UA-EK059T VivoBook 14 X420UA-EK073T VivoBook 14 X420UA-EK112T VivoBook 14 X420UA-EK127T VivoBook 14 X420UA-EK150TS VivoBook 14 X420UA-EK220T VivoBook 14 X420UA-EV075T VivoBook 15 X420FA-BV195T Vivobook 14 X420FA-EB085T Vivobook 14-X420FA-EK204T X420FA X420FA-EK013T X420FA-EK040T X420FA-EK051T X420FA-EK083T X420UA X420UA-8S vivobook 14 x412fa-ek295t x420fa-58bhdsp1 x420fa-ek037t

Replaces Part Numbers

0B200-03200000 C21N1819

Technical Specifications

Voltage7.7V
Amp Hours4900mAh
Capacity4900mAh
Rate37.73Wh
Net Weight170g /6.00 oz
Gross Weight310g /10.93 oz
Approximate Weight310g /10.93 oz
Dimension 183.80 x 135.30 x 5.00mm

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 A420UA shows the battery Wh rating in Windows as different from the original — is the new cell reporting wrong data?

The Wh figure Windows displays pulls from EEPROM metadata stored on the battery controller, not from the cell's actual chemistry. A fresh replacement cell carries different EEPROM values than the original, so the reported Wh may differ slightly from the sticker rating until the EC recalibrates. This is not a fault — the physical capacity is 37.73Wh as rated. Run two full discharge-to-hibernate and uninterrupted recharge cycles and the reported value will normalise.

The fuel gauge on my VivoBook 14 is jumping around erratically after swapping the battery — reads 80%, then 45%, then 70% within minutes.

The fuel gauge IC on the A420UA motherboard has to relearn the voltage-to-capacity curve of the new cell from scratch. Until it completes that calibration, it reads raw voltage and maps it against the old cell's curve, producing wild swings. This is expected behaviour for the first one to three cycles. Let the laptop discharge fully to hibernate cutoff, then charge uninterrupted to 100% without interruption — repeat twice and the gauge will lock onto a stable curve.

New battery installed but it won't charge above 80% — charging just stops there every time.

The A420UA BIOS includes a battery charge limit function that caps charging at 80% when enabled — this is a firmware setting, not a battery fault. Open MyASUS or the BIOS power settings and check whether "Battery Health Charging" or a charge limit mode is switched on. Disable it or set the mode to "Full Capacity" and the battery will charge to 100%. The physical cell ceiling is the full 4900mAh — nothing in the replacement restricts charge above 80%.

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 A420UA Replacement Battery, 7.7V, 4900mAh, 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