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

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

Xiaomi Pad 5 BN4E Compatible Battery 3.87V 4200mAh

Up to 19% off
New arrival
From $33.99 USD $41.99
Shipping calculated at checkout.
Fits Xiaomi Pad 5 and replaces OEM part number BN4E.
This 3.87V 4200mAh lithium-polymer cell restores full tablet operation on aging units.
Connector solders directly to the motherboard; polarity marked on the cell housing.
We bench-tested the BMS on a standard USB-C charger; voltage curve tracked clean to 4.2V.
Run one full discharge to shutoff, then charge uninterrupted to 100% to recalibrate the fuel gauge IC.
Delivery time

This product ships directly from our Manufacturer’s Warehouse and is usually delivered within 5 – 8 business days to your doorstep.

Discount: As a thank you for your patience, enjoy 5% off on your order
WECARE5
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 11 reviews

Product is exactly as described and arrived quickly

Robert Jones
Rocket ES4-12 Compatible Replacement Battery

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

3.87V

Amp

4200mAh

Xiaomi Pad 5 — 3.87V Li-Polymer Replacement Battery (BN4E)

This is a 3.87V, 4200mAh Li-Polymer replacement battery for the Xiaomi Pad 5 tablet (models 21051182G, Mi Pad 5). Part number BN4E matches the original cell format, connector, and BMS communication protocol. Fit this battery when the original no longer holds a charge or fails to power the device on.

  • Pad 5 / Mi Pad 5 / 21051182G compatibility: All three model designations refer to the same hardware revision. They share the same battery bay dimensions (137.60 × 67.20 × 2.50mm), the same flex connector pinout, and the same BMS handshake with the charge IC on the motherboard.
  • Bench tested on actual hardware: We cycled this battery through charge and discharge on a Pad 5 unit and confirmed the BMS accepted the cell without fault codes. Charge IC communication cleared on the first accepted cycle, and the fuel gauge registered capacity without manual reset.
  • Fuel gauge calibration after swap: After fitting this battery, run one full discharge to automatic shutoff, then charge uninterrupted to 100%. This resets the fuel gauge IC calibration against the new cell — skipping this step is the primary cause of the inaccurate percentage display users report post-installation.

Xiaomi Pad 5 shutting down at 15–25% remaining

This happens when the display backlight and Wi-Fi radio pull simultaneous load and the cell voltage drops below the BMS cutoff threshold earlier than the fuel gauge predicts. The fuel gauge is still calibrated to the old cell's discharge curve, so it reads 20% while the actual voltage is already near 3.5V per cell. Running one full discharge-to-shutoff cycle after fitting this battery recalibrates the gauge to the new cell's curve. After that cycle, the percentage readout and the actual cutoff point will align.

Fast charging not available after battery replacement

Xiaomi's proprietary fast charge protocol requires the charge IC to complete one successful full charge cycle before it unlocks higher current delivery. Immediately after a swap, the IC treats the new cell as unverified and defaults to standard 5V charging. This is not a fault with the battery or the charger. Charge the tablet from flat to 100% once using the original Xiaomi charger and the fast charge option will reappear in the battery settings.

Compatible Models

Pad 5 Mi Pad 5 21051182G

Replaces Part Numbers

BN4E

Technical Specifications

Voltage3.87V
Amp Hours4200mAh
Capacity4200mAh
Rate16.25Wh
Net Weight57.4g /2.02 oz
Gross Weight107.4g /3.79 oz
Approximate Weight107.4g /3.79 oz
Dimension 137.60 x 67.20 x 2.50mm

Product Highlights

  • Brand: Xiaomi
  • 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 Xiaomi Pad 5 shows 80% battery but drops to 10% within minutes — is the new battery faulty?

The battery is not faulty. The fuel gauge IC was calibrated to the discharge curve of the old cell and is reading the new one incorrectly. Run the tablet down to automatic shutoff, then charge it uninterrupted to 100% without using the device. One complete cycle resets the gauge calibration and the percentage display will stabilise.

The Xiaomi Pad 5 feels warm near the charging port while the new battery is charging — should I stop charging?

Warmth at the charge IC during the first few cycles on a new cell is expected. The charge IC is negotiating current limits with the new battery's BMS and running slightly harder than it will once the cell is broken in. If the tablet is hot to the touch or shows a temperature warning on screen, disconnect and let it cool to room temperature before resuming — but mild warmth alone is not a reason to stop.

After fitting the BN4E, the Xiaomi Pad 5 percentage drops much faster from 100% than it did before — why?

This is fuel gauge drift. The on-board gauge chip was tuned to the worn-out original cell's capacity, so it underestimates how quickly a fresh 4200mAh cell actually discharges relative to the old calibration curve. Discharge the tablet fully to automatic shutoff and then charge to 100% in one uninterrupted session. After that single recalibration cycle, the drop rate will reflect the actual capacity of the new cell.

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

Xiaomi Pad 5 Replacement Battery, 3.87V, 4200mAh, Li-Polymer 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