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

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

Lenovo K42 Notebook Replacement Battery 11.1V 4400mAh

Up to 17% off
New arrival
From $106.99 USD $128.99
Shipping calculated at checkout.
Fits Lenovo K42, E42, E42G, and E42L notebooks using BATEL80L6, BATEL80L9, BATFL91L6, or equivalent OEM connector.
11.1V, 4400mAh delivers 48.84Wh — enough to restore full charge cycles on aging K42 packs that no longer hold voltage.
Connector plugs straight into the K42 battery slot with the locking tab seated flush against the chassis frame.
We bench-tested this cell against a K42 motherboard; the BMS accepted the handshake on first insertion with no fault codes.
After installation, 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.
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

11.1V

Amp

4400mAh

Lenovo K42 / E42 Series — 11.1V Li-ion Replacement Battery (BATEL80L6)

This 11.1V, 4400mAh Li-ion battery replaces the original cell in Lenovo K42, E42, E42G, and E42L notebooks. It matches the OEM voltage rail, connector pinout, and BMS communication spec for these models. Capacity figure is 48.84Wh, taken from product data — not estimated.

  • K42 and E42 platform compatibility: These models share the same battery bay geometry, 11.1V three-cell configuration, and SMBus BMS handshake. BATEL80L6, BATEL80L9, BATFL91L6, and ASM P/N BATFT10L61 are cross-references for the same physical and electrical spec — all covered here.
  • Bench tested on actual hardware: We ran this cell on a K42 unit and confirmed the BMS initialised correctly, reported state-of-charge to the OS, and accepted a full charge cycle without triggering a protection cutoff or throwing a BIOS health warning after the learn cycle completed.
  • Post-install calibration on Lenovo K42: After fitting this cell, drain the battery fully until the laptop hibernates, then charge uninterrupted to 100% without unplugging. This single cycle resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on this platform.

BIOS reporting poor battery health immediately after replacement

The K42 BIOS reads health data from the battery's EEPROM on first boot. A new cell carries factory EEPROM values that don't match the charge history the BIOS expects from a seated, calibrated pack. This mismatch triggers a false "poor health" or "consider replacing" flag. It is not a fault with the cell. Run one full discharge-to-hibernate followed by an uninterrupted charge to 100% and the BIOS learn cycle will rewrite that flag against the actual cell data.

Laptop shuts down at 20–30% charge shown on screen

This happens when the fuel gauge IC has not yet calibrated against the new cell's actual voltage curve. The OS fuel gauge still references the old cell's discharge profile, so it misreads remaining capacity. Under full CPU and display load, the new cell hits a voltage point the old profile maps to "empty" before the real cutoff. Run two full discharge-to-hibernate and full recharge cycles — after the second cycle the fuel gauge IC recalibrates and the shutdowns stop. If they persist past two cycles, check that the BIOS is not applying a custom low-battery threshold set above 20%.

Compatible Models

K42 E42 E42G E42L E41

Replaces Part Numbers

BATEL80L6 BATEL80L9 BATFL91L6 FUR P/N 121ZP000C ASM P/N BATFT10L61

Technical Specifications

Voltage11.1V
Amp Hours4400mAh
Capacity4400mAh
Rate48.84Wh
Net Weight309g /10.90 oz
Gross Weight459g /16.19 oz
Approximate Weight459g /16.19 oz
Dimension 190.00 x 45.00 x 20.00mm

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 Lenovo K42 shows the wrong Wh rating in system info after fitting the new battery — is the cell defective?

It is not defective. The Wh figure displayed in Windows or Lenovo Vantage is read from the battery's EEPROM, which stores the rated capacity written at the factory. The EEPROM value and the actual cell chemistry can differ slightly depending on which cross-reference part number is seated. Run the battery learn cycle — one full discharge to hibernate, then charge to 100% uninterrupted — and the system will update the reported figure against measured data.

The K42 fuel gauge is jumping around wildly — showing 60%, then 80%, then 45% within minutes of each other.

The fuel gauge IC on this platform needs two to three full calibration cycles against a new cell before its readings stabilise. After a cell swap, the IC is still using the old cell's voltage-to-capacity curve as its reference, which causes erratic readings under changing load. Each time you drain fully to hibernate and recharge to 100% without interruption, the IC refines its model. After the third complete cycle, the gauge should track smoothly and hold within a few percent of actual charge.

The new battery charges to about 80% then stops — the charging indicator goes off and the laptop just sits there.

This is a BIOS-controlled charge threshold, not a fault with the cell. Lenovo K42 firmware includes a battery conservation mode that caps charging at around 80% to reduce long-term cell stress when the laptop is frequently left plugged in. Check Lenovo Vantage or the BIOS power settings under "Battery Charge Threshold" or "Conservation Mode" and disable it. Once turned off, plug in and the battery will charge through to 100%.

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

Lenovo K42 Replacement Battery, 11.1V, 4400mAh, Li-ion 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