Asus VivoBook 14 A412FA Replacement Battery 7.6V 4100mAh
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Asus VivoBook 14 A412FA Replacement Battery 7.6V 4100mAh - 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 VivoBook 14 A412FA Replacement Battery 7.6V 4100mAh - is backordered and will ship as soon as it is back in stock.
Voltage
7.6V
Amp
4100mAh
Asus VivoBook A412FA / A412UA Series — 7.6V Li-Polymer Replacement Battery (C21N1818)
This is a 7.6V 4100mAh (31.16Wh) Li-Polymer battery for the Asus VivoBook 14 A412FA, A412UA, A412UB, and related 14-inch notebooks. OEM part numbers covered include C21N1818, C21N1818-1, 0B200-03190600, and 0B200-03280500 among others. It fits the two-cell bay used across the A412 platform.
- A412 and A509 platform fit: These models share the same two-cell 7.6V Li-Polymer configuration, connector pinout, and BMS handshake protocol. The same battery communicates correctly with the EC firmware across all A412 and A509 variants listed under this SKU.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on an A412FA chassis. The BMS handshook within the first charge cycle, the EC recognised the cell, and charge termination triggered correctly at 8.6V full state. No fault codes were thrown.
- First-cycle learn reset on VivoBook firmware: After installing, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. This forces the BIOS battery learn cycle to reset against the new cell. Skip this step and the health indicator will likely show a warning or inaccurate state-of-charge for weeks.
BIOS reporting poor battery health immediately after fitting a new cell
The A412 EC reads health data from the old cell's EEPROM during every boot. When a new cell goes in, the EC has no charge history to reference and flags the battery as degraded or unknown. This is a firmware behaviour, not a fault with the replacement cell. Running one full discharge-to-hibernate then a full uninterrupted charge gives the EC enough data to recalibrate. After two to three cycles, the health report typically corrects itself.
Laptop shuts down at 20–30% shown on the fuel gauge after swap
This happens because the fuel gauge IC is still calibrated to the old cell's voltage curve. A new Li-Polymer cell holds voltage differently under combined CPU and display load, and the gauge miscalculates the remaining capacity. The cell hits the low-voltage cliff before the OS expects it, triggering an immediate shutdown. Run two full discharge-to-hibernate cycles followed by full charges — the fuel gauge IC re-maps its curve against the new cell and the readings stabilise around 3.6V per cell at the low end.
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
My VivoBook A412FA shows the new battery as 0% or "unknown" in Windows — did I get a dead cell?
The fuel gauge IC is reading EEPROM data from your old cell and has no calibration reference for the new one. The cell itself is fine. Run it down to hibernate-cutoff, then charge uninterrupted to 100%. Windows Battery Report should show a valid design capacity and a real charge percentage after that first complete cycle.
Windows shows 31Wh design capacity but the system info page reports a different Wh figure — which is right?
The figure Windows pulls from system info reflects the EEPROM-stored rated value from whatever cell was in the laptop last. The physical cell in this battery is rated at 31.16Wh at 7.6V and 4100mAh. After one full learn cycle, the EC overwrites the stored value with data from the new cell. Check Settings → Power & Sleep → Battery → Battery Report — the "Design Capacity" line there will update to match the new cell.
The A412 stops charging at 80% and won't go higher — is this a fault with the replacement battery?
This is the Asus Battery Health Charging feature in MyAsus or BIOS, not a battery fault. It caps charge at 80% to reduce cell stress during long periods of mains use. Open the MyAsus app, go to Battery Health Charging, and switch the mode from "Balanced" to "Full Capacity." The battery will charge to 100% on the next charge cycle.
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