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Lenovo K800 Replacement Battery BL189 3.7V 1900mAh

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From $28.99 USD $35.99
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Replaces Lenovo K800 smartphone BL189 battery pack.
3.7V 1900mAh cell powers the K800 through full daily cycles on stock firmware.
Connector slides into the K800 battery slot with single spring-tab retention on the left edge.
Bench testing showed the BMS accepted full charge cycles without early cutoff; voltage held steady under sustained load.
On first use after installation, run one complete discharge-charge cycle without enabling fast charging to let the fuel gauge IC recalibrate against the new cell curve.
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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By continuing with your purchase, you acknowledge and agree to the estimated 7–10 business day delivery timeframe.
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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.

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.

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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

3.7V

Amp

1900mAh

Lenovo K800 — 3.7V Li-ion Replacement Battery (BL189)

The BL189 is a 3.7V Li-ion cell rated at 1900mAh (7.03Wh), built to replace the original battery in the Lenovo K800 smartphone. The K800 is an Intel Atom-powered Android device from the early 2010s that uses a removable battery. When the original cell degrades and can no longer hold voltage under screen or modem load, this replacement restores full device function.

  • K800 fit confirmed: The BL189 connector, physical footprint (51.90 × 51.00 × 6.00mm), and voltage rail match the K800 battery bay exactly. No adapters or modifications required — the BMS handshake negotiates with the K800's charge IC as expected.
  • Bench tested on actual hardware: We cycled this cell through charge and discharge on the K800 platform. The BMS held charge cutoff at the correct upper voltage threshold and did not trip under normal screen-on and modem-active load conditions.
  • Fuel gauge recalibration on first use: After installation, run one full discharge down to auto-shutdown, then charge uninterrupted to 100% before using the device again. The K800's coulomb counter is calibrated to the old cell — skipping this step causes the percentage readout to drift or report inaccurate levels from day one.

Sudden shutdown at 20–30% on the BL189 replacement cell

The K800 shuts down mid-use because the phone's fuel gauge IC is still referencing the discharge curve of the worn original cell. When the new cell hits a voltage point the old curve mapped to 20–30%, the system triggers an emergency cutoff — even though real capacity remains. The fix is a full discharge-charge calibration cycle immediately after installation. After one complete cycle, the coulomb counter resets its reference and the percentage readout stabilises.

Device not powering on after the BL189 sat in storage

Li-ion cells that sit uncharged for extended periods can drop below 2.5V per cell, which triggers BMS lockout — the pack refuses to accept a charge or power the device as a protection measure. Connect the K800 to a wall charger and leave it undisturbed for 15–20 minutes before attempting to power on. Most BMS circuits will accept a trickle pre-charge at this stage and begin recovery. If the charge LED does not activate within 30 minutes, check that the charger output is at least 5V 1A.

Compatible Models

K800

Replaces Part Numbers

BL189

Technical Specifications

Voltage3.7V
Amp Hours1900mAh
Capacity1900mAh
Rate7.03Wh
Net Weight34.3g /1.21 oz
Gross Weight59g /2.08 oz
Approximate Weight59g /2.08 oz
Dimension 51.90 x 51.00 x 6.00mm

Product Highlights

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

Frequently Asked Questions

The K800 shows 25% battery and then just cuts off — why does this keep happening with the new cell?

The K800's fuel gauge IC is still referencing the discharge curve of the old, degraded cell. When the new BL189 reaches a voltage point the old curve mapped to roughly 20–30%, the system reads it as a critical low and forces a shutdown — even though the cell has charge left. Run one complete discharge to auto-shutdown followed by an uninterrupted charge to 100%. After that single cycle, the coulomb counter recalibrates to the new cell's curve and the early shutoffs stop.

The battery percentage on my K800 is jumping around erratically after I put in the new BL189 — is the battery faulty?

It is not faulty. The K800's coulomb counter accumulated data points from the original cell over months of use, and those reference values do not match the new BL189's discharge characteristics. The percentage readout will skip or jump until the fuel gauge IC has enough data from the replacement cell to build an accurate model. One full discharge-charge cycle — no interruptions — gives the IC enough data to lock in a stable curve. Erratic readings typically resolve within two to three cycles at most.

My K800 feels warm near the battery while charging the new BL189 — is that normal?

A new Li-ion cell has higher internal impedance than a cell that has been conditioned through several cycles. The K800's charge IC pushes current into a higher-resistance cell, and that resistance converts some energy to heat — which is why the back of the phone feels warmer than you expect in the first few charge sessions. The warmth should be mild and not uncomfortable to touch. If the phone becomes hot enough to be painful or the charge IC throttles back and charging slows dramatically, disconnect and let the device cool to room temperature before resuming.

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