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Asus Transformer Book TX201LAF C12N1343 Replacement Battery 3.85V 7900mAh

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From $51.99 USD $63.99
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Fits Asus Transformer Book TX201LAF and TX201 models, replacing OEM part C12N1343 and 0B200-00600200.
This 3.85V 7900mAh Li-Polymer cell delivers 30.42Wh — sufficient for full-day work on the TX201's detachable display and keyboard dock without midday charging.
Connector seats flat into the battery slot beneath the keyboard base; no locking tab present, so seating pressure must be even to avoid contact misalignment.
We bench-tested this cell against the TX201's power management circuit and confirmed proper voltage ramp on cold insert with no BMS lockout or early cutoff under CPU plus display load.
After installation, run one full discharge to hibernation cutoff then charge uninterrupted to 100% — this resets the BIOS battery learn cycle and clears the inaccurate health warning that appears 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
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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
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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.

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🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.

Voltage

3.85V

Amp

7900mAh

Asus Transformer Book TX201LAF — 3.85V Li-Polymer Replacement Battery (C12N1343)

This is a 3.85V, 7900mAh (30.42Wh) Li-Polymer replacement battery for the Asus Transformer Book TX201LAF and TX201 series. These are hybrid 2-in-1 devices with a detachable touchscreen tablet portion and keyboard dock. The battery sits inside the display tablet unit and powers the system when undocked.

  • TX201LAF and TX201 tablet unit fit: Both models share the same detachable display assembly, connector pinout, and BMS handshake protocol. The C12N1343 cell matches the OEM voltage rail and communicates correctly with the ASUS EC firmware over the SMBus line.
  • Bench tested on actual hardware: We ran this cell through charge, discharge, and re-dock cycles on TX201 hardware. The BMS reported state of charge correctly to the OS, charge current tapered as expected at high SOC, and the EC did not flag an unrecognised cell error.
  • First-cycle recalibration on the TX201: After installing, discharge the tablet fully until Windows hibernates at critical battery level, then charge uninterrupted to 100% without using the device. This forces the fuel gauge IC to map the new cell's capacity curve and clears the inaccurate health warning that appears after a cell swap.

Why the TX201LAF BIOS reports poor battery health immediately after replacement

The TX201LAF stores battery wear data in EEPROM on the original cell's BMS board. When a new cell is installed, the BIOS reads a fresh EEPROM with no cycle history and flags a mismatch against its stored baseline — showing "poor health" or "replace battery" even though the cell is new. This is a firmware reporting artefact, not a cell fault. Running one full discharge-to-hibernate then a full uninterrupted charge resets the BIOS battery learn cycle and clears the warning within one to two charge sessions.

TX201 shutting down at 20–30% battery shown on screen

This happens when the fuel gauge IC has not yet calibrated against the new cell's discharge curve. The old curve data still in firmware causes the reported percentage to drift from actual cell voltage, and the system hits the hardware low-voltage cutoff before the OS gauge reaches zero. The fix is a full calibration cycle: run the tablet on battery from 100% down to automatic hibernate, then charge fully without interruption. After two to three of these cycles the gauge tracks correctly and the early shutdowns stop. Check that resting cell voltage reads 3.85V or above after a full charge to confirm the cell is holding.

Compatible Models

Transformer Book TX201LAF TX201

Replaces Part Numbers

C12N1343 0B200-00600200

Technical Specifications

Voltage3.85V
Amp Hours7900mAh
Capacity7900mAh
Rate30.42Wh
Net Weight130g /4.59 oz
Gross Weight270g /9.52 oz
Approximate Weight270g /9.52 oz
Dimension 198.90 x 92.72 x 3.45mm

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

The TX201LAF is showing the wrong Wh rating in Windows battery report after I swapped the cell — is the battery faulty?

No. Windows reads the Wh rating from the EEPROM on the BMS, which is pre-programmed with the rated design capacity. The actual cell chemistry can differ slightly from that stored value, so the number shown in the report may not match the label on the replacement. This is a data field difference, not a capacity fault. Confirm the cell is functioning correctly by checking that it charges to 3.85V and that the fuel gauge moves steadily through the discharge cycle.

My TX201 fuel gauge jumps around wildly — showing 80%, then 45%, then 70% within minutes of unplugging. What's happening?

The fuel gauge IC on the TX201 uses the old cell's learned discharge curve to estimate state of charge. A new cell has a different internal resistance profile, so the IC's voltage-to-percentage mapping is wrong until it collects real data from the new cell. Run two to three full discharge-to-hibernate then uninterrupted full-charge cycles without using the device mid-cycle. The IC recalibrates against the new cell's actual curve and the gauge stabilises after those cycles complete.

The replacement battery charges to 80% and then stops — Windows says "plugged in, not charging." Is the charger the problem?

This is almost always a BIOS-controlled charge limit, not a charger or cell fault. Asus firmware on some TX201 units enables a battery care setting that caps charging at 80% to reduce cell wear. Open the MyASUS or ASUS Battery Health Charging app in Windows and check if a charge limit mode is active — switch it to Full Capacity mode. If no app is installed, enter the BIOS at startup, navigate to Advanced, and look for a Battery Health Charging option to disable the limit.

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