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

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

Huawei P Smart Z Replacement Battery HB446486ECW 3900mAh

Up to 21% off
New arrival
From $26.99 USD $33.99
Shipping calculated at checkout.
Fits Huawei P Smart Z, STK-L21, Y9s 2019, and P Smart Pro 2019 — replaces OEM part HB446486ECW.
Voltage 3.85V, capacity 3900mAh — supports the full power envelope on this mid-range display without undervoltage shutdown.
Connector type is Huawei proprietary with positive-first orientation — the locking tab seats flush against the phone frame.
Bench testing showed stable BMS handshake on first power-on with no early cutoff during 100% discharge at screen brightness peak.
On first use after installation, disable fast charging for one complete discharge-charge cycle — this recalibrates the fuel gauge IC against the new cell curve.
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

3.85V

Amp

3900mAh

Huawei P Smart Z / Y9s 2019 — 3.85V Li-Polymer Replacement Battery (HB446486ECW)

This is a 3900mAh Li-Polymer cell at 3.85V, replacing OEM part HB446486ECW. It fits the Huawei P Smart Z (STK-L21), Y9s 2019, and P Smart Pro 2019, among other variants sharing the same battery bay and connector pinout. Swap this in when the original cell no longer holds a charge or the device fails to power on.

  • STK-L21 and Y9s 2019 platform compatibility: These models share the same 3.85V power rail, identical flex connector, and the same BMS handshake protocol. One cell covers the full variant range without modification.
  • Bench tested on actual hardware: We cycled this cell through charge and discharge on STK-L21 hardware. The BMS accepted the cell without error flags, and the charge IC stepped through CC/CV phases correctly at both standard and fast-charge current levels.
  • Fuel gauge recalibration on first install: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated coulomb counter.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage cliff issue, not a capacity fault. Under heavy screen or modem load, a new cell pulls the bus voltage down sharply at the lower end of the discharge curve. The device's protection circuit reads this as a critical undervoltage event and trips before the displayed percentage reaches zero. The fuel gauge IC is still calibrated to the old cell's curve. One full discharge-to-shutdown and charge-to-100% cycle resets the coulomb counter against the new cell, and the shutdowns stop.

Device won't power on after the battery sat discharged in storage

Li-Polymer cells below approximately 2.5V trigger a BMS lockout as a hard protection against cell reversal. The phone appears completely dead — no boot, no charge indicator. Connect to a wall adapter, not a PC USB port, and leave it for 15–20 minutes without touching the power button. The charge IC applies a low trickle current to bring the cell back above the BMS re-enable threshold, typically around 3.0V, before normal charging resumes.

Compatible Models

P Smart Z STK-L21 Y9s 2019 P Smart Pro 2019 STK-LX1 Y9 Prime 2019 STK-L22

Replaces Part Numbers

HB446486ECW

Technical Specifications

Voltage3.85V
Amp Hours3900mAh
Capacity3900mAh
Rate15.02Wh
Net Weight52.8g /1.86 oz
Gross Weight102.8g /3.63 oz
Approximate Weight102.8g /3.63 oz
Dimension 85.20 x 63.92 x 4.00mm

Product Highlights

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

Frequently Asked Questions

The P Smart Z shows the wrong battery percentage after I swapped the cell — it jumped from 45% to 10% out of nowhere. What's happening?

The fuel gauge IC is still running the discharge curve it learned from the old cell. It has no accurate map of where the new cell's voltage sits relative to remaining capacity, so the percentage reading becomes unreliable — often jumping or collapsing under load. Run one complete drain-to-shutdown followed by an uninterrupted charge to 100% with fast charging disabled. That single cycle gives the coulomb counter enough data to recalibrate against the new cell, and the erratic percentage readings stop.

Huawei fast charging isn't working on the replacement battery — it's just doing a slow charge. Is something wrong with the cell?

This is normal on the first cycle after a cell swap. The proprietary fast-charge handshake between the charge IC and the BMS requires the cell to be above a minimum voltage threshold and within a calibrated state-of-charge window before the device allows high-current delivery. On the first charge from a low state, the IC defaults to standard current as a safety measure. Charge once at standard speed all the way to 100%, then unplug and reconnect — fast charging will engage on the following cycle once the BMS has confirmed cell integrity.

The phone feels warm near the battery area during the first few charges after replacing the cell. Should I be concerned?

Some warmth on the first one or two cycles is expected with a new Li-Polymer cell. A fresh cell has slightly higher internal impedance than a broken-in one, so the charge IC dissipates a little more energy as heat during the constant-current phase. This drops off noticeably after two or three full cycles as the cell's impedance settles. If the device stays hot to the touch throughout the full charge or gets warm during standby with no active charging, stop charging and check that the flex connector is fully seated — a partial connection raises contact resistance and generates heat at the joint.

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

Huawei P Smart Z Replacement Battery, 3.85V, 3900mAh, 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