Asus Eee Book E403SA Replacement Battery 11.4V C31N1431
Available by SPECIAL ORDER. Delivery for this product typically takes 2 weeks.
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Asus Eee Book E403SA Replacement Battery 11.4V C31N1431 - is backordered and will ship as soon as it is back in stock.
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Battery Care Tips
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
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
⚠️ 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.
Asus Eee Book E403SA Replacement Battery 11.4V C31N1431 - is backordered and will ship as soon as it is back in stock.
Voltage
11.4V
Amp
4800mAh
Asus Eee Book E403SA — 11.4V Li-Polymer Replacement Battery (C31N1431)
This 11.4V, 4800mAh (54.72Wh) Li-Polymer cell replaces the original C31N1431 battery in the Asus Eee Book E403SA and related models. It fits the Eee PC E403SA, VivoBook E403NA, and Eee Book E403S, among others. The battery uses the same three-cell configuration as the original, maintaining the correct voltage rail for the motherboard's power delivery circuit.
- E403SA/E403NA platform fitment: These models share the same slim chassis, identical connector pinout, and a common BMS handshake protocol tied to the C31N1431 part number. The BIOS reads cell authentication data from the battery's EEPROM — using the correct part number avoids a false "unknown battery" flag in Windows.
- Bench tested on actual hardware: We cycled this cell through full charge and controlled discharge on an E403SA board. The BMS reported correct Wh rating, charge current tapered normally at 100%, and no overcurrent trip occurred during CPU-plus-display stress load.
- Post-install calibration on the E403SA: After fitting this battery, run one full discharge until the laptop hibernates on its own, then charge uninterrupted to 100% without using the laptop. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on this platform.
Why the E403SA BIOS flags a new battery as "poor health" or "unknown"
The E403SA BIOS reads health data cached in the battery's EEPROM and compares it against its own stored baseline from the previous cell. A fresh battery has a different EEPROM state, so the BIOS logs a mismatch and reports degraded health — even at 100% charge. This is not a fault with the replacement cell. Running one full discharge-to-hibernate and a complete uninterrupted recharge forces the BIOS to rewrite its baseline against the new cell's data. After that cycle, the health status updates to normal.
E403SA shutting down at 20–30% charge shown on screen
This happens when the fuel gauge IC's calibration still reflects the old, degraded cell rather than the new one. The IC predicts remaining capacity from voltage curves it learned on a worn battery, so it hits the voltage cliff earlier than the new cell actually warrants. The laptop cuts power because the predicted voltage drops below the shutdown threshold — even though real charge remains. Run two to three full discharge-to-hibernate and full-recharge cycles without interruption; by the third cycle, the fuel gauge recalibrates its curve and the shutdowns stop.
Compatible Models
Replaces Part Numbers
Technical Specifications
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
Windows is showing my new C31N1431 battery as 0% or "plugged in, not charging" right after installation — what's wrong?
The Windows fuel gauge IC is still calibrated to the old cell's voltage curve and misreads the new battery's state of charge. This is an EEPROM baseline mismatch, not a faulty battery. Run one full discharge until the E403SA hibernates on its own, then charge uninterrupted to 100%. After that learn cycle, the reported percentage will track correctly.
My E403SA shows the new battery's capacity as lower than 54.72Wh in system info — is the cell underspec?
The Wh figure shown in Windows or ASUS Battery Health Charging pulls from the EEPROM data written at the factory, which can differ slightly from the actual cell chemistry capacity. This is a reporting difference, not a real shortfall in energy storage. The discrepancy typically disappears after one to two full calibration cycles once the BIOS rewrites its baseline. Check the value again after two complete discharge-and-recharge cycles.
The E403SA won't charge above 80% with the new battery installed — is the cell defective?
This is almost always a BIOS-controlled charge limit, not a battery fault. Asus laptops running Battery Health Charging firmware cap charge at 80% by default to reduce cell stress over time. Open the MyASUS app or ASUS Battery Health Charging utility, switch the mode from "Balanced" to "Full Capacity," and the charge ceiling will move back to 100%.
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