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Lenovo ThinkPad X100e 11.1V Replacement Battery 0A36278

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From $100.99 USD $121.99
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Fits Lenovo ThinkPad X100e 2876 and replaces OEM part 0A36278, ASM 42T4784, ASM 42T4786, ASM 42T4788, and equivalent FRU numbers listed by Lenovo.
Supplies 11.1V at 4400mAh capacity for full portable runtime on this ultraportable ultrabook without external power.
Connector seats into the X100e battery bay with keyed plastic latch; orientation marked on the cell itself prevents reverse insertion.
We bench tested this cell on an X100e 2876 with the BMS at rest voltage of 12.1V; full charge completed in under two hours with no cutoff faults.
After installing, run one full discharge to hibernation cutoff then charge uninterrupted to 100% — this resets the BIOS battery learn cycle and clears inaccurate health warnings that appear after every cell swap.
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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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⚠️ 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

11.1V

Amp

4400mAh

Lenovo ThinkPad X100e 2876 — 11.1V Li-ion Replacement Battery (0A36278)

This 11.1V, 4400mAh (48.84Wh) Li-ion battery fits the Lenovo ThinkPad X100e series, including the 2876, 3506, and 3507 variants. It replaces the original cell when capacity has degraded or the pack no longer holds charge. Voltage and connector match the OEM spec — the BIOS recognises it as a known battery type on insertion.

  • X100e series compatibility: The 2876, 3506, and 3507 share the same 11.1V three-cell architecture and physical bay dimensions. All variants use the same connector pinout and BMS handshake protocol, so one cell fits the entire X100e line without modification.
  • Bench tested on actual hardware: We cycled this cell on a ThinkPad X100e under sustained CPU and display load. The BMS held voltage above the 9.6V cutoff threshold through full discharge, and charge acceptance reached rated capacity without interruption.
  • First-install calibration on the X100e: After fitting the new cell, run a full discharge to hibernate 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.

BIOS reporting battery health as poor after replacement

The ThinkPad BIOS reads health data from the battery's EEPROM on every boot. When a new cell arrives, its EEPROM cycle count and learn data differ from the old pack, so the BIOS flags it as degraded before any calibration has run. This is not a fault with the cell — it is a mismatch between stored EEPROM history and actual cell state. Running one full discharge-to-hibernate followed by an uninterrupted charge to 100% rewrites the learn data and clears the warning on the next boot.

Laptop shutting down at 20–30% charge shown

This happens when the fuel gauge IC has not yet calibrated against the new cell's actual voltage curve. The IC still maps percentage readings to the old cell's discharge profile, so it under-reports remaining capacity and the system hits the low-voltage shutdown threshold while the gauge still shows 20–30%. The fix is two to three full discharge-and-recharge cycles so the fuel gauge IC relearns the voltage-to-capacity curve of the new cell. After calibration, the displayed percentage and actual cutoff voltage align — target 10.8V or below at the point the laptop hibernates.

Compatible Models

ThinkPad X100e 2876 ThinkPad X100e ThinkPad X100e 3506 ThinkPad X100e 3507 ThinkPad X100e 3508 ThinkPad Edge 11" NVY4LFR ThinkPad Edge 11" NVZ24FR ThinkPad Edge 11" NVZ3BGE ThinkPad X120e

Replaces Part Numbers

0A36278 ASM 42T4784 ASM 42T4786 ASM 42T4788 42T4889 42T4891 42T4893 42T4894 42T4895 42T4897 57Y4558 57Y4559 FRU 42T4781 FRU 42T4783 FRU 42T4785 FRU 42T4787 FRU 42T4789

Technical Specifications

Voltage11.1V
Amp Hours4400mAh
Capacity4400mAh
Rate48.84Wh
Net Weight314.4g /11.09 oz
Gross Weight454.4g /16.03 oz
Approximate Weight454.4g /16.03 oz
Dimension 150.00 x 115.50 x 13.10mm

Product Highlights

  • Brand: Lenovo
  • Manufacturer: CS
  • Series: Standard
  • Color: Black
  • Product Type: Li-ion
  • Battery Type: Li-ion
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

My ThinkPad X100e BIOS says "battery unknown" right after I put in the new cell — is it faulty?

It is not faulty. The BIOS reads identity and health data stored in the battery's EEPROM, and a fresh cell has no learn history from this specific laptop. Run one full discharge to hibernate cutoff, then charge uninterrupted to 100%. That learn cycle writes the calibration data the BIOS expects, and the unknown flag clears on the next boot.

Windows is showing the new battery as 48Wh but the ThinkPad power manager reports a different Wh rating — which is right?

The figure in ThinkPad Power Manager is pulled from the EEPROM's rated design capacity, which reflects the cell chemistry specification rather than a live measurement. Windows may read from a different data register. The physical cell in this pack is rated at 48.84Wh — that is the authoritative value. The discrepancy disappears after one full calibration cycle once the fuel gauge IC maps real capacity against the EEPROM data.

The new cell stopped charging at 80% and will not go higher — is the charger at fault?

The charger is not at fault. Lenovo's BIOS on the X100e series includes a charge threshold feature that caps charging at 80% when Conservation Mode is active in Lenovo Vantage or the legacy Power Manager utility. Open Lenovo Vantage, navigate to Power, and check the charge threshold setting. Switch it from Conservation Mode to Normal Mode and the cell will charge to 100%.

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